The US government filed a lawsuit against American Airlines on Thursday charging that the carrier denied benefits to three of its pilots during their service with the Naval Reserve and Air National Guard.

The complaint filed in US District Court in Dallas alleges that American Airlines conducted an audit of the leave taken for military service by its pilots in 2001.

Based on that audit, the government charges, American Airlines cut the employment benefits of pilots who had taken military leave, while not reducing the same benefits of pilots who had taken similar types of non-military leave.

American Airlines spokesman Tim Wagner said the company was reviewing the lawsuit and had no immediate comment.

Named in the suit were Mark Woodall and Michael McMahon, who serve as pilots in the Naval Reserve, and Paul Madson, a pilot in the South Dakota Air National Guard.

The Justice Department said it was its first class action complaint under the Uniformed Services Employment and Reemployment Rights Act that became law in 1994.

"This nation depends on our reservists to faithfully carry out their duty. No reservists, indeed no members of the armed forces, should ever be punished or discriminated against for answering the call of duty," Assistant Attorney General for Civil Rights Wan Kim said in a statement.

The Justice Department said it filed the lawsuit after efforts to settle the pilots' complaints had failed.