The strongly worded resolution says the Affordable Care Act will drive up the costs of union-sponsored health plans to the point that workers and employers are forced to abandon them. Labor unions still support the law's overall goals of reducing health costs and bringing coverage to all Americans, the resolution says, but adds that the law is being implemented in a way that is "highly disruptive" to union health care plans.

Some individual unions have complained about the law's impact for months. The resolution marks the first time the nation's largest labor federation has gone on record embracing that view. Unions were among the most enthusiastic backers of the law when it passed in 2010.

A labor official told The Associated Press that White House officials had been calling labor leaders for days to urge them not to voice their concerns in the form of a resolution. The official, who wasn't authorized to discuss the conversations publicly and requested anonymity, said many union leaders insisted that they wanted to highlight their concerns.