LOS ANGELES, Dec 4 (Reuters) – Union and management negotiators agreed on Tuesday to the intervention of a federal mediator in a bid to settle a week-old strike by clerical workers at the ports of Los Angeles and Long Beach that has idled most of America’s biggest container port complex.

The agreement to mediation, announced by Los Angeles Mayor Antonio Villaraigosa, came after an all-night bargaining session that a spokesman for the Harbor Employers Association, representing shippers and terminal operators, said had left the parties “still far apart.”

There was no immediate word on when talks would resume.

With mounting economic losses estimated at several billion dollars, the strike marks the largest cargo traffic disruption at the twin Southern California harbor facilities since a 10-day lockout of longshoremen at several West Coast ports in 2002.