diff --git a/libraries/stdlib/js/src/kotlin/concurrent.kt b/libraries/stdlib/js/src/kotlin/concurrent.kt
index fd9943c0c87..33a081b7b47 100644
--- a/libraries/stdlib/js/src/kotlin/concurrent.kt
+++ b/libraries/stdlib/js/src/kotlin/concurrent.kt
@@ -8,10 +8,10 @@ package kotlin
 import kotlin.contracts.*
 
 
-@Deprecated("Use Synchronized annotation from kotlin.jvm package", ReplaceWith("kotlin.jvm.Synchronized"), level = DeprecationLevel.WARNING)
+@Deprecated("Do not use Synchronized annotation in pure Kotlin/JS code", level = DeprecationLevel.ERROR)
 public typealias Synchronized = kotlin.jvm.Synchronized
 
-@Deprecated("Use Volatile annotation from kotlin.jvm package", ReplaceWith("kotlin.jvm.Volatile"), level = DeprecationLevel.WARNING)
+@Deprecated("Do not use Volatile annotation in pure Kotlin/JS code", level = DeprecationLevel.ERROR)
 public typealias Volatile = kotlin.jvm.Volatile
 
 @kotlin.internal.InlineOnly