President Trump announced Wednesday that the U.S. will begin to deduct foreign aid from countries whose residents illegally enter the United States.

"Many of these countries we give tremendous amounts of aid to. Tens of millions of dollars. And we're working on a plan to deduct a lot of the aid," Trump said at an event in New York denouncing the Salvadoran gang MS-13.

"We're going to work out something where every time someone comes in from a certain country, we're going to deduct a rather large amount of money from what we give them in aid, if we give them aid at all," Trump said. "We may just not give them aid at all."

Trump did not specify which countries would be targeted, but spoke after another panelist mentioned foreign countries refusing to accept deportees.

"They'll let you think they're trying to stop this. They are not trying to stop it," Trump said. "I think they encourage people... They don't want the people that we're getting."

"Despite all of the reports I hear, I don't believe they're helping us one bit. and it may be that's the way life is," he said. "We know where these people are coming from. We're looking at our whole aid structure and it's going to be changed very radically. It's already started."

MS-13 was founded in Los Angeles in the 1980s among refugees from El Salvador, where a U.S.-backed government fought communist rebels, with human rights violations on both sides. Many of its young members today illegally entered the U.S.

According to USAID, El Salvador received $75 million in U.S. aid in fiscal 2016. The amount fluctuates, and spiked to $332 million in 2015. Mexico, the top home country of illegal immigrants in the U.S., received $87 million in foreign aid in 2016, according to USAID.

Trump previously has threatened foreign aid penalties, notably in December after various countries that receive aid voted to condemn his decision to move the U.S. embassy in Israel to Jerusalem.