U.S. House of Representatives Speaker John Boehner called on President Barack Obama on Thursday to soon send Congress the administration's plan for using military force against Islamic State.

The Obama administration has argued that its campaign of airstrikes in Iraq and Syria against Islamic State militants is legal, based on authorization passed in the early 2000s under President George W. Bush for the Iraq War and fighting al-Qaida and associated groups.

But several members of Congress have said it would be preferable to debate and pass a new authorization for combating Islamic State fighters, who have killed thousands of people while seizing swaths of territory in Iraq and Syria.

Republicans in particular have urged the Democratic president to make a formal request while others, mostly Democrats, have said lawmakers should pass their own measure and then send it Obama for his signature.

Republican Boehner said his party's lawmakers would work with the White House to pass an authorization approved if he sends one, asking him to do so quickly in the new Congress in which Republicans control both the House and Senate.

"I've continued to remind the president that historically, the commander in chief has identified the need for the use of military force, written a new authorization for that force, sent it to the Hill, and typically also worked to build bipartisan support for such a resolution," Boehner said at his first weekly news conference of the new Congress.