diff --git a/api/handler/api.go b/api/handler/api.go
index 45b4b3949..f16e1ca8a 100644
--- a/api/handler/api.go
+++ b/api/handler/api.go
@@ -27,13 +27,14 @@ type (
 
 	// Config contains data which handler needs to keep.
 	Config struct {
-		Policy             PlacementPolicy
-		XMLDecoder         XMLDecoderProvider
-		DefaultMaxAge      int
-		NotificatorEnabled bool
-		CopiesNumber       uint32
-		ResolveZoneList    []string
-		IsResolveListAllow bool // True if ResolveZoneList contains allowed zones
+		Policy                     PlacementPolicy
+		XMLDecoder                 XMLDecoderProvider
+		DefaultMaxAge              int
+		NotificatorEnabled         bool
+		CopiesNumber               uint32
+		ResolveZoneList            []string
+		IsResolveListAllow         bool // True if ResolveZoneList contains allowed zones
+		CompleteMultipartKeepalive time.Duration
 	}
 
 	PlacementPolicy interface {
diff --git a/api/handler/multipart_upload.go b/api/handler/multipart_upload.go
index 258aabfe0..e33de971c 100644
--- a/api/handler/multipart_upload.go
+++ b/api/handler/multipart_upload.go
@@ -400,9 +400,15 @@ func (h *handler) CompleteMultipartUploadHandler(w http.ResponseWriter, r *http.
 		Parts: reqBody.Parts,
 	}
 
+	// Next operations might take some time, so we want to keep client's
+	// connection alive. To do so, gateway sends periodic white spaces
+	// back to the client the same way as Amazon S3 service does.
+	stopPeriodicResponseWriter := periodicXMLWriter(w, h.cfg.CompleteMultipartKeepalive)
+
 	uploadData, extendedObjInfo, err := h.obj.CompleteMultipartUpload(r.Context(), c)
 	if err != nil {
-		h.logAndSendError(w, "could not complete multipart upload", reqInfo, err, additional...)
+		logAndSendError := h.periodicWriterErrorSender(stopPeriodicResponseWriter())
+		logAndSendError(w, "could not complete multipart upload", reqInfo, err, additional...)
 		return
 	}
 	objInfo := extendedObjInfo.ObjectInfo
@@ -418,7 +424,8 @@ func (h *handler) CompleteMultipartUploadHandler(w http.ResponseWriter, r *http.
 			NodeVersion: extendedObjInfo.NodeVersion,
 		}
 		if _, err = h.obj.PutObjectTagging(r.Context(), tagPrm); err != nil {
-			h.logAndSendError(w, "could not put tagging file of completed multipart upload", reqInfo, err, additional...)
+			logAndSendError := h.periodicWriterErrorSender(stopPeriodicResponseWriter())
+			logAndSendError(w, "could not put tagging file of completed multipart upload", reqInfo, err, additional...)
 			return
 		}
 	}
@@ -426,12 +433,14 @@ func (h *handler) CompleteMultipartUploadHandler(w http.ResponseWriter, r *http.
 	if len(uploadData.ACLHeaders) != 0 {
 		key, err := h.bearerTokenIssuerKey(r.Context())
 		if err != nil {
-			h.logAndSendError(w, "couldn't get gate key", reqInfo, err)
+			logAndSendError := h.periodicWriterErrorSender(stopPeriodicResponseWriter())
+			logAndSendError(w, "couldn't get gate key", reqInfo, err)
 			return
 		}
 		acl, err := parseACLHeaders(r.Header, key)
 		if err != nil {
-			h.logAndSendError(w, "could not parse acl", reqInfo, err)
+			logAndSendError := h.periodicWriterErrorSender(stopPeriodicResponseWriter())
+			logAndSendError(w, "could not parse acl", reqInfo, err)
 			return
 		}
 
@@ -441,11 +450,13 @@ func (h *handler) CompleteMultipartUploadHandler(w http.ResponseWriter, r *http.
 		}
 		astObject, err := aclToAst(acl, resInfo)
 		if err != nil {
-			h.logAndSendError(w, "could not translate acl of completed multipart upload to ast", reqInfo, err, additional...)
+			logAndSendError := h.periodicWriterErrorSender(stopPeriodicResponseWriter())
+			logAndSendError(w, "could not translate acl of completed multipart upload to ast", reqInfo, err, additional...)
 			return
 		}
 		if _, err = h.updateBucketACL(r, astObject, bktInfo, sessionTokenSetEACL); err != nil {
-			h.logAndSendError(w, "could not update bucket acl while completing multipart upload", reqInfo, err, additional...)
+			logAndSendError := h.periodicWriterErrorSender(stopPeriodicResponseWriter())
+			logAndSendError(w, "could not update bucket acl while completing multipart upload", reqInfo, err, additional...)
 			return
 		}
 	}
@@ -460,23 +471,25 @@ func (h *handler) CompleteMultipartUploadHandler(w http.ResponseWriter, r *http.
 		h.log.Error("couldn't send notification: %w", zap.Error(err))
 	}
 
-	bktSettings, err := h.obj.GetBucketSettings(r.Context(), bktInfo)
-	if err != nil {
-		h.logAndSendError(w, "could not get bucket settings", reqInfo, err)
-	}
-
 	response := CompleteMultipartUploadResponse{
 		Bucket: objInfo.Bucket,
 		ETag:   objInfo.HashSum,
 		Key:    objInfo.Name,
 	}
 
-	if bktSettings.VersioningEnabled() {
-		w.Header().Set(api.AmzVersionID, objInfo.VersionID())
-	}
+	// Here we previously set api.AmzVersionID header for versioned bucket.
+	// It is not possible after #60, because we introduced periodic white
+	// space XML writer to keep connection with the client.
 
-	if err = api.EncodeToResponse(w, response); err != nil {
-		h.logAndSendError(w, "something went wrong", reqInfo, err)
+	headerIsWritten := stopPeriodicResponseWriter()
+	if headerIsWritten {
+		if err = api.EncodeToResponseNoHeader(w, response); err != nil {
+			h.logAndSendErrorNoHeader(w, "something went wrong", reqInfo, err)
+		}
+	} else {
+		if err = api.EncodeToResponse(w, response); err != nil {
+			h.logAndSendError(w, "something went wrong", reqInfo, err)
+		}
 	}
 }
 
@@ -732,3 +745,12 @@ func periodicXMLWriter(w io.Writer, dur time.Duration) (stop func() bool) {
 
 	return stop
 }
+
+// periodicWriterErrorSender returns handler function to send error. If header is
+// alreay written by periodic XML writer, do not send HTTP and XML headers.
+func (h *handler) periodicWriterErrorSender(headerWritten bool) func(http.ResponseWriter, string, *api.ReqInfo, error, ...zap.Field) {
+	if headerWritten {
+		return h.logAndSendErrorNoHeader
+	}
+	return h.logAndSendError
+}
diff --git a/cmd/s3-gw/app.go b/cmd/s3-gw/app.go
index bcbb65d4b..7c04876c1 100644
--- a/cmd/s3-gw/app.go
+++ b/cmd/s3-gw/app.go
@@ -654,6 +654,8 @@ func (a *App) initHandler() {
 		cfg.ResolveZoneList = a.cfg.GetStringSlice(cfgResolveBucketDeny)
 	}
 
+	cfg.CompleteMultipartKeepalive = a.cfg.GetDuration(cfgKludgeCompleteMultipartUploadKeepalive)
+
 	var err error
 	a.api, err = handler.New(a.log, a.obj, a.nc, cfg)
 	if err != nil {
diff --git a/cmd/s3-gw/app_settings.go b/cmd/s3-gw/app_settings.go
index 470abfa04..f97e397bb 100644
--- a/cmd/s3-gw/app_settings.go
+++ b/cmd/s3-gw/app_settings.go
@@ -115,6 +115,7 @@ const ( // Settings.
 
 	// Kludge.
 	cfgKludgeUseDefaultXMLNSForCompleteMultipartUpload = "kludge.use_default_xmlns_for_complete_multipart"
+	cfgKludgeCompleteMultipartUploadKeepalive          = "kludge.complete_multipart_keepalive"
 
 	// Command line args.
 	cmdHelp      = "help"
@@ -258,6 +259,7 @@ func newSettings() *viper.Viper {
 
 	// kludge
 	v.SetDefault(cfgKludgeUseDefaultXMLNSForCompleteMultipartUpload, false)
+	v.SetDefault(cfgKludgeCompleteMultipartUploadKeepalive, 10*time.Second)
 
 	// Bind flags
 	if err := bindFlags(v, flags); err != nil {
diff --git a/config/config.env b/config/config.env
index b62452c2f..23b5596cf 100644
--- a/config/config.env
+++ b/config/config.env
@@ -130,3 +130,5 @@ S3_GW_RESOLVE_BUCKET_ALLOW=container
 
 # Enable using default xml namespace `http://s3.amazonaws.com/doc/2006-03-01/` when parse`CompleteMultipartUpload` xml body.
 S3_GW_KLUDGE_USE_DEFAULT_XMLNS_FOR_COMPLETE_MULTIPART=false
+# Set timeout between whitespace transmissions during CompleteMultipartUpload processing.
+S3_GW_KLUDGE_COMPLETE_MULTIPART_KEEPALIVE=10s
diff --git a/config/config.yaml b/config/config.yaml
index ccc631e2d..afd495046 100644
--- a/config/config.yaml
+++ b/config/config.yaml
@@ -153,3 +153,5 @@ resolve_bucket:
 kludge:
   # Enable using default xml namespace `http://s3.amazonaws.com/doc/2006-03-01/` when parse`CompleteMultipartUpload` xml body.
   use_default_xmlns_for_complete_multipart: false
+  # Set timeout between whitespace transmissions during CompleteMultipartUpload processing.
+  complete_multipart_keepalive: 10s
diff --git a/docs/configuration.md b/docs/configuration.md
index 4bc4c463a..115382779 100644
--- a/docs/configuration.md
+++ b/docs/configuration.md
@@ -504,8 +504,10 @@ Workarounds for non-standard use cases.
 ```yaml
 kludge:
   use_default_xmlns_for_complete_multipart: false
+  complete_multipart_keepalive: 10s
 ```
 
-| Parameter                                  | Type   | SIGHUP reload | Default value | Description                                                                                                                 |
-|--------------------------------------------|--------|---------------|---------------|-----------------------------------------------------------------------------------------------------------------------------|
-| `use_default_xmlns_for_complete_multipart` | `bool` | yes           | false         | Enable using default xml namespace `http://s3.amazonaws.com/doc/2006-03-01/` when parse `CompleteMultipartUpload` xml body. |
+| Parameter                                  | Type       | SIGHUP reload | Default value | Description                                                                                                                 |
+|--------------------------------------------|------------|---------------|---------------|-----------------------------------------------------------------------------------------------------------------------------|
+| `use_default_xmlns_for_complete_multipart` | `bool`     | yes           | false         | Enable using default xml namespace `http://s3.amazonaws.com/doc/2006-03-01/` when parse `CompleteMultipartUpload` xml body. |
+| `complete_multipart_keepalive`             | `duration` | no            | 10s           | Set timeout between whitespace transmissions during CompleteMultipartUpload processing.                                     |