With a border deal hanging in the balance and the Iowa caucuses a month away, Donald Trump amplified his attack on immigrants at a rally in New Hampshire on Saturday.

“They’re poisoning the blood of our country,” the former president said. “They’ve poisoned mental institutions and prisons all over the world. Not just in South America, not just the three or four countries that we think about, but all over the world they’re coming into our country from Africa, from Asia.”

While in the White House, Trump sought to deter immigration by building a wall on the U.S.-Mexico border, building some 450 miles of fencing along the nearly 2,000-mile border, much of which replaced existing barriers. In addition to strict border security measures, his administration also implemented a travel ban for people from several predominantly Muslim countries.