By JUSTIN PRITCHARD

Associated Press

LOS ANGELES (AP) _ Nearly 1,000 dockworkers briefly walked off their jobs Tuesday at the massive ports of Los Angeles and Long Beach, disrupting the movement of international cargo before a mediator ordered them back.

The action came as the union representing dockworkers at 29 West Coast ports negotiates a new contract, but it was not directly related to those talks. Instead, workers left their posts at four of the ports’ 14 terminals in solidarity with truck drivers involved in a separate dispute.

The West Coast waterfront has an acrimonious labor history, including in 2002 when employers alleged longshoremen were deliberately slowing down work and locked them out for 10 days, costing the U.S. economy billions of dollars.

During this year’s negotiations, both the International Longshore and Warehouse Union and Pacific the Maritime Association, which represents international shipping lines and port terminal operators, have said they do not want disruptions in trade.

On Tuesday morning, however, union members at three terminals in Los Angeles and one in Long Beach walked out after pickets representing truck drivers set up lines at six terminals. A spokeswoman for the drivers, Barb Maynard, said pickets targeted the terminals after trucks from three companies they have been trying to unionize went there to load or drop off containers.

Within two hours, an arbitrator ruled that a walkout in solidarity was not permissible and ordered dockworkers to resume loading and unloading ships. By afternoon, the flow of cargo was returning to normal. In all, about 900 workers walked off, maritime association spokesman Steve Getzug said.

The ports of Los Angeles and Long Beach are the primary West Coast gateway for hundreds of billions of dollars of annual trade with Asia.

While their six-year contract initially expired Monday, the maritime association and union extended it until Friday. That reinstated the arbitration process and the ability of employers to force dockworkers back to their posts _ a process that disappears when the contract is not in place.