Obama says it will take 'some time' but IS will lose

United States President Barack Obama has said that the Islamic State (IS) will lose as he asked Congress to authorize use of military force to take on the terror outfit.

He said, "Our coalition is on the offensive. Isil [IS] is on the defensive, and Isil is going to lose," reported the BBC.

Flanked by the Vice-President Joe Biden, and the U.S. secretaries of state and defence at the White House, Obama said that he was convinced that the U.S. should not get dragged into another prolonged was in the Middle East but added that fighting IS would take "some time."

However, he added that this is did not signal that it was an "endless war."

Obama called on the lawmakers to put up a united front in the fight against the IS.

The U.S.-led coalition has been conducting air strikes against the IS since last year.

This is the first time a U.S. President has sought Congressional authorization to use military force since President George W. Bush in 2002, ahead of the invasion of Iraq.