Much of the humanitarian crisis on the border is being driven by families fleeing violence in Central America, but the United States is working closely with authorities in El Salvador and in the “northern triangle” countries to try to keep gang members from the notorious MS-13 gang from showing up on U.S. soil, Attorney General William Barr said in an interview on Friday.

“The Justice Department has a very robust program down here to help the government attack this drug problem,” Barr told Fox News’ Bill Hemmer, who traveled to the Central American country to interview him. “We’re working very closely with them.”

As a result of the cooperative efforts, the murder rate has dropped by half in El Salvador in the past three years, said Barr.

“In three years in the northern triangle, we’ve been able to charge over 7,000 members of MS-13 and the 18th Street gang,” said Barr. “It is a great partnership we have with them, and it is helping us in the United States because MS-13 gang members that we can get down here are not going to be coming up to the United States.”

In addition, the intelligence that’s gathered can be used to prosecute MS-13 members in the United States, said Barr.

“Last August, we prosecuted six MS-13 members in New Jersey using intelligence that was gathered down here,” he added.

This is Barr’s first trip to El Salvador as US Attorney General.