Delivering a warning to Democratic lawmakers who have objected to his plans to construct a wall along the U.S.-Mexico frontier, Trump called them “obstructionists” and said that it was time for the U.S. to crack down on illegal immigration.

“If we have to close down our government, we’re building that wall,” Trump told thousands of supporters gathered in Phoenix for a campaign-style rally. “One way or the other, we’re going to get that wall.”