WASHINGTON, May 1 (Reuters) - The United States on Wednesday accused Russia of violating the international chemical weapons ban by deploying the choking agent chloropicrin against Ukrainian troops and using riot control agents "as a method of warfare" in Ukraine.

"The use of such chemicals is not an isolated incident and is probably driven by Russian forces' desire to dislodge Ukrainian forces from fortified positions and achieve tactical gains on the battlefield," the State Department said in a statement.

The Russian embassy did not immediately respond to a request for comment.

Chloropicrin is listed as a banned choking agent by the Hague-based Organization for the Prohibition of Chemical Weapons (OPCW), which was created to implement and monitor compliance with the 1993 Chemical Weapons Convention (CWC).