Lawmakers who had been trying to block President Donald Trump from striking Iran are now demanding an emergency vote after he moved ahead with a sweeping military operation early Saturday.

Within hours of Trump announcing that U.S. forces were carrying out what he called “major combat operations,” Sen. Tim Kaine and Rep. Ro Khanna, who are leading the war powers push in the Senate and House, called on Congress to immediately reconvene and vote on their resolutions.

“These strikes are a colossal mistake, and I pray they do not cost our sons and daughters in uniform and at embassies throughout the region their lives,” Kaine said.

“The Senate should immediately return to session and vote on my War Powers Resolution to block the use of U.S. forces in hostilities against Iran. Every single Senator needs to go on the record about this dangerous, unnecessary, and idiotic action,” he added.