Obama says he has authority to take action against IS

US President Barack Obama meets with Congressional leaders in the Oval Office of the White House in Washington to discuss his plan to combat Islamic State militants operating in Iraq and Syria Sept 9, 2014. From left are: Senate Minority Leader Mitch McConnell, Speaker of the House John Boehner, Obama, Senate Majority Leader Harry Reid and Democratic House Leader Nancy Pelosi. [Photo/Agencies]

Obama, US Vice President Joe Biden and Congressional leaders had a "productive" discussion and the leaders expressed their support for efforts to degrade and ultimately destroy IS, the White House said in a statement. The Islamic State, or the Islamic State of Iraq and the Levant (ISIL), is an al-Qaida splinter group also known as the Islamic State of Iraq and Syria (ISIS).

The meeting came ahead of a speech on Wednesday evening in which Obama will lay out his plan to fight the extremist group.

Obama told the Leaders that he would welcome action by Congress that would "aid the overall effort" and demonstrate to the world that the United States is united in defeating the threat from IS, said the statement.

Obama reiterated his belief that the nation is stronger and its efforts more effective when he and Congress work together to combat a national security threat like IS, according to the statement.

White House spokesman Josh Earnest said Tuesday that Obama will unveil a broad explanation of the "next phase" of US efforts against Islamic militants, but not provide other concrete details such as the cost and the timeline for the operation.

"In the context of the speech that the president is preparing for tomorrow, I wouldn't expect something that's quite that detailed," Earnest told a press briefing.