The United Auto Workers union has sued General Motors Corp., saying the automaker owes it $450 million for retiree health care.

In the lawsuit filed Tuesday in federal court in Detroit, the UAW said that in 2007, GM agreed to pay $450 million to settle a UAW claim against auto supplier Delphi Corp. as part of Delphi's emergence from bankruptcy protection. Delphi is GM's former parts division.

The UAW said the agreement should still be in effect even though GM went through its own bankruptcy reorganization last year. The UAW said it demanded the payment from GM on Oct. 29.

According to court documents, GM responded with a letter rejecting the union's demand.

The UAW says the money should go to a union-run retiree health care fund.