US dock workers and port operators have reached a tentative deal that will immediately end a three-day strike.

Some 45,000 union workers walked off the job at seaports on the U.S. East and Gulf Coasts on Oct. 1, cutting off vital trade arteries just weeks ahead of the nation's presidential election.

The largest union representing dockworkers in the United States said an anticipated port strike will begin on Tuesday as negotiations have reportedly stalled.