The union says a strike at the US East Coast port is scheduled to begin on Tuesday

A strike at ports on the US East Coast and Gulf of Mexico will begin on Tuesday, the International Longshoremen's Union said on Sunday, signaling action that could cause delays and disrupt supply chains.

“The United States Naval Alliance… refuses to address half a century of wage oppression,” the union said in a statement. The United States Marine Alliance, known as USMX, represents employers in the coastal industry in the East and Gulf Coast.

If union members stop working at ports from Maine to Texas, it will be the first coast-wide strike since 1977.

It was not clear whether any negotiations were taking place or were planned before Monday's midnight deadline.

Earlier, President Joe Biden said he had no intention of intervening to prevent a strike if dockworkers failed to secure a new contract by the October 1 deadline.

“It's collective bargaining. I don't believe in Taft-Hartley,” he told reporters.

Presidents can intervene in labor disputes that threaten national security or safety by imposing an 80-day cooling-off period under the federal Taft-Hartley Act.