The union representing roughly 340,000 U.S. drivers, package handlers and loaders at United Parcel Service said on Wednesday the parcel delivery firm had "walked away from the bargaining table".
UPS did not immediately respond to a request for comment.
Teamsters said in a tweet that UPS presented an offer, which was unanimously rejected by the union's national negotiating committee.
(Reporting by Jahnavi Nidumolu in Bengaluru; Editing by Shounak Dasgupta)