Two Republicans in U.S. House of Representatives introduced a legislation Tuesday to put an end to U.S. military involvement in Libya unless explicitly authorized by Congress.

The bill was sponsored by Reps. Timothy Johnson and Justin Amash. Their bill would cut off all funding related to the Pentagon intervention in Libya.

The Congressmen contend the administration's role in the military campaign in Libya is unconstitutional without the blessing of the Congress.

Under the constitution, the legislative branch has the exclusive right to declare war.

"Constitutionally, it is indisputable that Congress must be consulted prior to an act of war unless there is an imminent threat against this country. The President has not done so," Johnson said.

Secretary of Defense Robert Gates conceded in a Sunday talkshow that Libya did not pose "an actual or imminent threat" to the United States before the military campaign against it began. President Barack Obama said Monday in a major speech on Libya that he consulted with "bipartisan leadership of Congress" before ordering military action.

According to the Pentagon, Libyan intervention has cost U.S. taxpayers about 550 million dollars to date, and the costs should hold steady at around 40 million per month from now on.

Around 60 percent of the cost is from munitions, such as the 192 Tomahawk missiles U.S. military fired at 1 to 1.5 million dollars apiece. The rest were used to troops deployment and other combat costs, including additional fuel.

Navy Adm. Gary Roughead, chief of naval operations, said last week most of the cost incurred in the Libyan mission have already been paid for, because Navy vessels were already budgeted for global deployment, and the munitions used in the operation represent a small fraction of U.S. inventory, and there's no need to replenish.