Attorney General William Barr is in El Salvador to discuss a crackdown on criminals flowing into the United States, and a federal prosecutor argued Friday that the trip sends "strong message" to gangs like MS-13.

The notorious street gang, which has infiltrated the northern Virginia area especially in recent years, primarily hails from the Northern Triangle countries of El Salvador, Honduras and Guatemala.

During an appearance on "America's Newsroom," Eastern District of Virginia U.S. Attorney Zach Terwilliger commended the attorney general for his trip and attempts to better understand the gang.

"MS-13 has been active in the northern Virginia area for quite some time and I spent the first nine years of my legal career in battle against them," Terwilliger said. "I've had a front row seat to their callousness and the tremendous violence that they can bring to a community."

A number of horrific murders allegedly committed by MS-13 members have occurred this year alone, including a teenage boy who was stabbed up to 100 times. Last year, a number of MS-13 members pleaded guilty to hacking a man to death, and in February, 11 members were indicted in the kidnapping and murder of two teens.

"Making his first trip to El Salvador I believe sends a very strong message about our priorities, and his priorities as far as reducing violent crime," Terwilliger said. "As you just heard the attorney general mention, it is critical we have a strong partnership with the northern triangle countries."

Attorney General Barr spoke exclusively with "America's Newsroom" host Bill Hemmer while in El Salvador, during which time he condemned the "political circus" being waged against him and discussed his decision to further investigate the origins of the Mueller investigation.

US ATTORNEY JOHN DURHAM HAS BEEN REVIEWING ORIGINS OF RUSSIA PROBE 'FOR WEEKS:' SOURCE

LISTEN TO THE FULL INTERVIEW ON THE LATEST "HEMMER TIME" PODCAST

While in El Salvador, Barr will meet with law enforcement officials from all three Northern Triangle countries in an attempt to better understand MS-13.

Terwilliger said on Friday that more communication between the United States and Northern Triangle countries is necessary to quell the surge of gang violence in Virginia and abroad.

"As we deport gang members at the end of their sentences or violations we have to have law enforcement sharing of information between ourselves and El Salvador, Honduras and Guatemala," he said.

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"If we can't get a handle of what is happening with MS-13 in the Northern Triangle, the problem will be imported to the United States."

It won't be easy, but Terwilliger said constant vigilance is necessary to stop the gang once and for all

"My experience with MS-13 is you can keep them down but if you let up a little bit the void will be filled by younger, more aggressive gang members," he said.

"My point is we have to keep up the pressure. We need to keep driving. In my experience, if we don't do that, it will crop up again."