President-elect Donald Trump on Monday confirmed he would declare a national emergency to carry out his campaign promise of mass deportations of migrants living in the U.S. without legal permission.

Overnight, Trump responded to a social media post from Judicial Watch’s Tom Fitton, who said earlier this month there are reports the incoming administration is preparing such a declaration and to use “military assets” to deport the migrants.

“TRUE!!!” Trump wrote.

Trump pledged to get started on mass deportations as soon as he enters office.

“On Day 1, I will launch the largest deportation program in American history to get the criminals out,” he said during a rally at Madison Square Garden in the closing days of the presidential race. “I will rescue every city and town that has been invaded and conquered, and we will put these vicious and bloodthirsty criminals in jail, then kick them the hell out of our country as fast as possible.”