diff --git a/src/uct/ib/dc/accel/dc_mlx5.c b/src/uct/ib/dc/accel/dc_mlx5.c
index b1a6de312f4..6351ef39764 100644
--- a/src/uct/ib/dc/accel/dc_mlx5.c
+++ b/src/uct/ib/dc/accel/dc_mlx5.c
@@ -236,16 +236,6 @@ uct_dc_mlx5_iface_atomic_post(uct_dc_mlx5_iface_t *iface, uct_dc_mlx5_ep_t *ep,
     uct_rc_txqp_add_send_op(txqp, &desc->super);
 }
 
-static inline void uct_dc_mlx5_iface_add_send_comp(uct_dc_mlx5_iface_t *iface,
-                                                   uct_dc_mlx5_ep_t *ep,
-                                                   uct_completion_t *comp)
-{
-    UCT_DC_MLX5_TXQP_DECL(txqp, txwq);
-
-    UCT_DC_MLX5_IFACE_TXQP_GET(iface, &ep->super, txqp, txwq);
-    uct_rc_txqp_add_send_comp(&iface->super.super, txqp, comp, txwq->sig_pi);
-}
-
 static ucs_status_t UCS_F_ALWAYS_INLINE
 uct_dc_mlx5_ep_atomic_op_post(uct_ep_h tl_ep, unsigned opcode, unsigned size,
                               uint64_t value, uint64_t remote_addr, uct_rkey_t rkey)
@@ -657,8 +647,9 @@ ucs_status_t uct_dc_mlx5_ep_flush(uct_ep_h tl_ep, unsigned flags, uct_completion
 {
     uct_dc_mlx5_iface_t *iface = ucs_derived_of(tl_ep->iface,
                                                 uct_dc_mlx5_iface_t);
-    uct_dc_mlx5_ep_t    *ep    = ucs_derived_of(tl_ep, uct_dc_mlx5_ep_t);
+    uct_dc_ep_t         *ep    = ucs_derived_of(tl_ep, uct_dc_ep_t);
     ucs_status_t        status;
+    UCT_DC_MLX5_TXQP_DECL(txqp, txwq);
 
     status = uct_dc_ep_flush(tl_ep, flags, comp);
     if (status == UCS_OK) {
@@ -666,8 +657,10 @@ ucs_status_t uct_dc_mlx5_ep_flush(uct_ep_h tl_ep, unsigned flags, uct_completion
     }
 
     if (status == UCS_INPROGRESS) {
-        ucs_assert(ep->super.dci != UCT_DC_EP_NO_DCI);
-        uct_dc_mlx5_iface_add_send_comp(iface, ep, comp);
+        ucs_assert(ep->dci != UCT_DC_EP_NO_DCI);
+        UCT_DC_MLX5_IFACE_TXQP_GET(iface, ep, txqp, txwq);
+        status = uct_rc_txqp_add_flush_comp(&iface->super.super, txqp, comp,
+                                            txwq->sig_pi);
     }
     return status;
 }
diff --git a/src/uct/ib/dc/verbs/dc_verbs.c b/src/uct/ib/dc/verbs/dc_verbs.c
index 0ee2da7800c..dfac71622d9 100644
--- a/src/uct/ib/dc/verbs/dc_verbs.c
+++ b/src/uct/ib/dc/verbs/dc_verbs.c
@@ -567,6 +567,7 @@ ucs_status_t uct_dc_verbs_ep_flush(uct_ep_h tl_ep, unsigned flags, uct_completio
                                                  uct_dc_verbs_iface_t);
     uct_dc_verbs_ep_t    *ep    = ucs_derived_of(tl_ep, uct_dc_verbs_ep_t);
     ucs_status_t         status;
+    uint8_t              dci;
 
     status = uct_dc_ep_flush(tl_ep, flags, comp);
     if (status == UCS_OK) {
@@ -574,9 +575,13 @@ ucs_status_t uct_dc_verbs_ep_flush(uct_ep_h tl_ep, unsigned flags, uct_completio
     }
 
     if (status == UCS_INPROGRESS) {
-        ucs_assert(ep->super.dci != UCT_DC_EP_NO_DCI);
-        uct_dc_verbs_iface_add_send_comp(iface, ep, comp);
+        dci = ep->super.dci;
+        ucs_assert(dci != UCT_DC_EP_NO_DCI);
+        status = uct_rc_txqp_add_flush_comp(&iface->super.super,
+                                            &iface->super.tx.dcis[dci].txqp,
+                                            comp, iface->dcis_txcnt[dci].pi);
     }
+
     return status;
 }
 
diff --git a/src/uct/ib/rc/accel/rc_mlx5_ep.c b/src/uct/ib/rc/accel/rc_mlx5_ep.c
index 656975dce98..5c6599cb46b 100644
--- a/src/uct/ib/rc/accel/rc_mlx5_ep.c
+++ b/src/uct/ib/rc/accel/rc_mlx5_ep.c
@@ -534,9 +534,12 @@ ucs_status_t uct_rc_mlx5_ep_flush(uct_ep_h tl_ep, unsigned flags,
         sn = ep->tx.wq.sig_pi;
     }
 
-    uct_rc_txqp_add_send_comp(&iface->super, &ep->super.txqp, comp, sn);
-    UCT_TL_EP_STAT_FLUSH_WAIT(&ep->super.super);
-    return UCS_INPROGRESS;
+    status = uct_rc_txqp_add_flush_comp(&iface->super, &ep->super.txqp, comp, sn);
+    if (status == UCS_INPROGRESS) {
+        UCT_TL_EP_STAT_FLUSH_WAIT(&ep->super.super);
+    }
+
+    return status;
 }
 
 ucs_status_t uct_rc_mlx5_ep_fc_ctrl(uct_ep_t *tl_ep, unsigned op,
diff --git a/src/uct/ib/rc/base/rc_ep.c b/src/uct/ib/rc/base/rc_ep.c
index 4b36befd952..71f09e02e75 100644
--- a/src/uct/ib/rc/base/rc_ep.c
+++ b/src/uct/ib/rc/base/rc_ep.c
@@ -369,6 +369,13 @@ void uct_rc_ep_send_op_completion_handler(uct_rc_iface_send_op_t *op,
     uct_rc_iface_put_send_op(op);
 }
 
+void uct_rc_ep_flush_op_completion_handler(uct_rc_iface_send_op_t *op,
+                                           const void *resp)
+{
+    uct_invoke_completion(op->user_comp, UCS_OK);
+    ucs_mpool_put(op);
+}
+
 ucs_status_t uct_rc_ep_pending_add(uct_ep_h tl_ep, uct_pending_req_t *n,
                                    unsigned flags)
 {
@@ -501,6 +508,8 @@ void uct_rc_txqp_purge_outstanding(uct_rc_txqp_t *txqp, ucs_status_t status,
         op->flags &= ~UCT_RC_IFACE_SEND_OP_FLAG_INUSE;
         if (op->handler == uct_rc_ep_send_op_completion_handler) {
             uct_rc_iface_put_send_op(op);
+        } else if (op->handler == uct_rc_ep_flush_op_completion_handler) {
+            ucs_mpool_put(op);
         } else {
             desc = ucs_derived_of(op, uct_rc_iface_send_desc_t);
             ucs_mpool_put(desc);
diff --git a/src/uct/ib/rc/base/rc_ep.h b/src/uct/ib/rc/base/rc_ep.h
index 3d9b955c92b..2e303ddb48d 100644
--- a/src/uct/ib/rc/base/rc_ep.h
+++ b/src/uct/ib/rc/base/rc_ep.h
@@ -242,6 +242,9 @@ void uct_rc_ep_get_bcopy_handler_no_completion(uct_rc_iface_send_op_t *op,
 void uct_rc_ep_send_op_completion_handler(uct_rc_iface_send_op_t *op,
                                              const void *resp);
 
+void uct_rc_ep_flush_op_completion_handler(uct_rc_iface_send_op_t *op,
+                                           const void *resp);
+
 ucs_status_t uct_rc_ep_pending_add(uct_ep_h tl_ep, uct_pending_req_t *n,
                                    unsigned flags);
 
@@ -357,6 +360,28 @@ uct_rc_txqp_add_send_comp(uct_rc_iface_t *iface, uct_rc_txqp_t *txqp,
     uct_rc_txqp_add_send_op_sn(txqp, op, sn);
 }
 
+static UCS_F_ALWAYS_INLINE ucs_status_t
+uct_rc_txqp_add_flush_comp(uct_rc_iface_t *iface, uct_rc_txqp_t *txqp,
+                           uct_completion_t *comp, uint16_t sn)
+{
+    uct_rc_iface_send_op_t *op;
+
+    if (comp != NULL) {
+        op = (uct_rc_iface_send_op_t*)ucs_mpool_get(&iface->tx.flush_mp);
+        if (ucs_unlikely(op == NULL)) {
+            ucs_error("Failed to allocate flush completion");
+            return UCS_ERR_NO_MEMORY;
+        }
+
+        op->flags     = 0;
+        op->user_comp = comp;
+        uct_rc_txqp_add_send_op_sn(txqp, op, sn);
+        VALGRIND_MAKE_MEM_DEFINED(op, sizeof(*op)); /* handler set by mpool init */
+    }
+
+    return UCS_INPROGRESS;
+}
+
 static UCS_F_ALWAYS_INLINE void
 uct_rc_txqp_completion_op(uct_rc_iface_send_op_t *op, const void *resp)
 {
diff --git a/src/uct/ib/rc/base/rc_iface.c b/src/uct/ib/rc/base/rc_iface.c
index 07e43792f03..bc2f4493028 100644
--- a/src/uct/ib/rc/base/rc_iface.c
+++ b/src/uct/ib/rc/base/rc_iface.c
@@ -135,6 +135,24 @@ static ucs_mpool_ops_t uct_rc_fc_pending_mpool_ops = {
     .obj_cleanup   = NULL
 };
 
+static void
+uct_rc_iface_flush_comp_init(ucs_mpool_t *mp, void *obj, void *chunk)
+{
+    uct_rc_iface_t *iface      = ucs_container_of(mp, uct_rc_iface_t, tx.flush_mp);
+    uct_rc_iface_send_op_t *op = obj;
+
+    op->handler = uct_rc_ep_flush_op_completion_handler;
+    op->flags   = 0;
+    op->iface   = iface;
+}
+
+static ucs_mpool_ops_t uct_rc_flush_comp_mpool_ops = {
+    .chunk_alloc   = ucs_mpool_chunk_malloc,
+    .chunk_release = ucs_mpool_chunk_free,
+    .obj_init      = uct_rc_iface_flush_comp_init,
+    .obj_cleanup   = NULL
+};
+
 static void uct_rc_iface_tag_query(uct_rc_iface_t *iface,
                                    uct_iface_attr_t *iface_attr,
                                    size_t max_inline, size_t max_iov)
@@ -488,6 +506,7 @@ static ucs_status_t uct_rc_iface_tx_ops_init(uct_rc_iface_t *iface)
 {
     const unsigned count = iface->config.tx_ops_count;
     uct_rc_iface_send_op_t *op;
+    ucs_status_t status;
 
     iface->tx.ops_buffer = ucs_calloc(count, sizeof(*iface->tx.ops_buffer),
                                       "rc_tx_ops");
@@ -496,14 +515,22 @@ static ucs_status_t uct_rc_iface_tx_ops_init(uct_rc_iface_t *iface)
     }
 
     iface->tx.free_ops = &iface->tx.ops_buffer[0];
-    for (op = iface->tx.ops_buffer; op < iface->tx.ops_buffer + count - 1; ++op) {
+    for (op = iface->tx.ops_buffer; op < iface->tx.ops_buffer + count; ++op) {
         op->handler = uct_rc_ep_send_op_completion_handler;
         op->flags   = UCT_RC_IFACE_SEND_OP_FLAG_IFACE;
         op->iface   = iface;
-        op->next    = op + 1;
+        op->next    = (op == (iface->tx.ops_buffer + count - 1)) ? NULL : (op + 1);
     }
-    iface->tx.ops_buffer[count - 1].next = NULL;
-    return UCS_OK;
+
+    /* Create memory pool for flush completions. Can't just alloc a certain
+     * size buffer, because number of simultaneous flushes is not limited by
+     * CQ or QP resources. */
+    status = ucs_mpool_init(&iface->tx.flush_mp, 0, sizeof(*op), 0,
+                            UCS_SYS_CACHE_LINE_SIZE, 256,
+                            UINT_MAX, &uct_rc_flush_comp_mpool_ops,
+                            "flush-comps-only");
+
+    return status;
 }
 
 static void uct_rc_iface_tx_ops_cleanup(uct_rc_iface_t *iface)
@@ -522,6 +549,8 @@ static void uct_rc_iface_tx_ops_cleanup(uct_rc_iface_t *iface)
                  total_count- free_count, total_count);
     }
     ucs_free(iface->tx.ops_buffer);
+
+    ucs_mpool_cleanup(&iface->tx.flush_mp, 1);
 }
 
 #if IBV_EXP_HW_TM
diff --git a/src/uct/ib/rc/base/rc_iface.h b/src/uct/ib/rc/base/rc_iface.h
index d555fcf5983..cd8dbc9c5ce 100644
--- a/src/uct/ib/rc/base/rc_iface.h
+++ b/src/uct/ib/rc/base/rc_iface.h
@@ -228,8 +228,9 @@ struct uct_rc_iface {
     uct_ib_iface_t              super;
 
     struct {
-        ucs_mpool_t             mp;      /* pool for send descriptors */
-        ucs_mpool_t             fc_mp;   /* pool for FC grant pending requests */
+        ucs_mpool_t             mp;       /* pool for send descriptors */
+        ucs_mpool_t             fc_mp;    /* pool for FC grant pending requests */
+        ucs_mpool_t             flush_mp; /* pool for flush completions */
         /* Credits for completions.
          * May be negative in case mlx5 because we take "num_bb" credits per
          * post to be able to calculate credits of outstanding ops on failure.
diff --git a/src/uct/ib/rc/verbs/rc_verbs_ep.c b/src/uct/ib/rc/verbs/rc_verbs_ep.c
index e3a0b31372f..d8abee6feaf 100644
--- a/src/uct/ib/rc/verbs/rc_verbs_ep.c
+++ b/src/uct/ib/rc/verbs/rc_verbs_ep.c
@@ -521,9 +521,13 @@ ucs_status_t uct_rc_verbs_ep_flush(uct_ep_h tl_ep, unsigned flags,
         }
     }
 
-    uct_rc_txqp_add_send_comp(&iface->super, &ep->super.txqp, comp, ep->txcnt.pi);
-    UCT_TL_EP_STAT_FLUSH_WAIT(&ep->super.super);
-    return UCS_INPROGRESS;
+    status = uct_rc_txqp_add_flush_comp(&iface->super, &ep->super.txqp, comp,
+                                        ep->txcnt.pi);
+    if (status == UCS_INPROGRESS) {
+        UCT_TL_EP_STAT_FLUSH_WAIT(&ep->super.super);
+    }
+
+    return status;
 }
 
 ucs_status_t uct_rc_verbs_ep_fc_ctrl(uct_ep_t *tl_ep, unsigned op,
diff --git a/test/gtest/common/test_helpers.h b/test/gtest/common/test_helpers.h
index a2493427c6f..afcfa24c065 100644
--- a/test/gtest/common/test_helpers.h
+++ b/test/gtest/common/test_helpers.h
@@ -78,7 +78,7 @@
 #define ASSERT_UCS_OK_OR_INPROGRESS(_expr) \
     do { \
         ucs_status_t _status = (_expr); \
-        if ((status) != UCS_OK && (_status) != UCS_INPROGRESS) { \
+        if (((_status) != UCS_OK) && ((_status) != UCS_INPROGRESS)) { \
             UCS_TEST_ABORT("Error: " << ucs_status_string(_status)); \
         } \
     } while (0)
diff --git a/test/gtest/uct/ib/test_dc.cc b/test/gtest/uct/ib/test_dc.cc
index 83612f7f7fc..cb105dafda5 100644
--- a/test/gtest/uct/ib/test_dc.cc
+++ b/test/gtest/uct/ib/test_dc.cc
@@ -22,7 +22,7 @@ extern "C" {
     _UCT_INSTANTIATE_TEST_CASE(_test_case, dc_mlx5)
 
 
-class test_dc : public uct_test {
+class test_dc : public test_rc {
 public:
     virtual void init() {
         uct_test::init();
@@ -71,7 +71,6 @@ class test_dc : public uct_test {
     }
 
 protected:
-    entity *m_e1, *m_e2;
 
     struct dcs_comp {
         uct_completion_t uct_comp;
@@ -404,6 +403,10 @@ UCS_TEST_P(test_dc, dcs_ep_purge_pending) {
     EXPECT_EQ(0, iface->tx.stack_top);
 }
 
+UCS_TEST_P(test_dc, stress_iface_ops) {
+    test_iface_ops();
+}
+
 UCT_DC_INSTANTIATE_TEST_CASE(test_dc)
 
 
diff --git a/test/gtest/uct/ib/test_rc.cc b/test/gtest/uct/ib/test_rc.cc
index 9ad5f670073..8b336e720f3 100644
--- a/test/gtest/uct/ib/test_rc.cc
+++ b/test/gtest/uct/ib/test_rc.cc
@@ -35,6 +35,55 @@ void test_rc::connect()
     uct_iface_set_am_handler(m_e2->iface(), 0, am_dummy_handler, NULL, 0);
 }
 
+// Check that iface tx ops buffer and flush comp memory pool are moderated
+// properly when we have communication ops + lots of flushes
+void test_rc::test_iface_ops()
+{
+    check_caps(UCT_IFACE_FLAG_PUT_ZCOPY);
+    int cq_len = 16;
+
+    if (UCS_OK != uct_config_modify(m_iface_config, "RC_TX_CQ_LEN",
+                                    ucs::to_string(cq_len).c_str())) {
+        UCS_TEST_ABORT("Error: cannot enable random DCI policy");
+    }
+
+    entity *e = uct_test::create_entity(0);
+    m_entities.push_back(e);
+    e->connect(0, *m_e2, 0);
+
+    mapped_buffer sendbuf(1024, 0ul, *e);
+    mapped_buffer recvbuf(1024, 0ul, *m_e2);
+    uct_completion_t comp;
+    comp.count = cq_len * 512; // some big value to avoid func invocation
+    comp.func  = NULL;
+
+    UCS_TEST_GET_BUFFER_IOV(iov, iovcnt, sendbuf.ptr(), sendbuf.length(),
+                            sendbuf.memh(),
+                            m_e1->iface_attr().cap.am.max_iov);
+    // For _x transports several CQEs can be consumed per WQE, post less put zcopy
+    // ops, so that flush would be sucessfull (otherwise flush will return
+    // NO_RESOURCES and completion will not be added for it).
+    for (int i = 0; i < cq_len / 3; i++) {
+        ASSERT_UCS_OK_OR_INPROGRESS(uct_ep_put_zcopy(e->ep(0), iov, iovcnt,
+                                                     recvbuf.addr(),
+                                                     recvbuf.rkey(), &comp));
+
+        // Create some stress on iface (flush mp):
+        // post 10 flushes per every put.
+        for (int j = 0; j < 10; j++) {
+            ASSERT_UCS_OK_OR_INPROGRESS(uct_ep_flush(e->ep(0), 0, &comp));
+        }
+    }
+
+    flush();
+}
+
+UCS_TEST_P(test_rc, stress_iface_ops) {
+    test_iface_ops();
+}
+
+UCT_RC_INSTANTIATE_TEST_CASE(test_rc)
+
 
 class test_rc_max_wr : public test_rc {
 protected:
diff --git a/test/gtest/uct/ib/test_rc.h b/test/gtest/uct/ib/test_rc.h
index d4437035fe9..c5cd27174c7 100644
--- a/test/gtest/uct/ib/test_rc.h
+++ b/test/gtest/uct/ib/test_rc.h
@@ -41,6 +41,8 @@ class test_rc : public uct_test {
         uct_test::short_progress_loop(delta_ms);
     }
 
+    void test_iface_ops();
+
     static ucs_status_t am_dummy_handler(void *arg, void *data, size_t length,
                                          unsigned flags) {
         return UCS_OK;