On Aug. 28, about 2,500 passenger service workers at Los Angeles International Airport (LAX) called a strike and walked off their jobs after labor talks broke down with their employers, threatening to cripple operations at the world's fifth busiest airport.

The workers, including janitors, wheelchair attendants, baggage handlers, security guards, are demanding pay raises, more health benefits and better job training.

Negotiations broke off earlier in the day when airport service contractors refused the latest proposal by the union, according to union spokesman Mike Chavez. The spokesman said a federal mediator has been present during the most recent round of labor talks.

"The contractors we've been negotiating with have refused to give a serious response to the proposals we have put forth in improving the quality of jobs and security at the airport," Chavez said.

Union members voted last week to authorize their leaders to call a strike if negotiations continued to stall with nine private firms charged with hiring airport service workers at LAX. The union's labor pacts with all nine employers have been expiring since last month.

The strike will likely cause inconvenience and trouble for air travelers using LAX during the Labor Day long weekend, which kicks off on Aug. 29. An estimated 825,000 travelers are expected to board flights during the upcoming holiday weekend.

Airport officials declined to immediately comment on the strike, and union leaders didn't say how long the strike will last.