Former CIA Director James Woolsey, a vocal advocate of the 2003 U.S.-led invasion of Iraq who promoted allegations that Saddam Hussein harbored illegal weapons, will serve as a senior national security adviser to Republican presidential candidate Donald Trump, the campaign announced on Monday.

Woolsey's hiring contrasted with Trump's repeated assertions that he was a stalwart opponent of the invasion, although he initially supported it.

In the announcement, Woolsey said he supports Trump's plan to expand the U.S. military, which calls for ending Pentagon budget caps and spending billions of dollars for additional troops, ships and aircraft.