Arrests of gang members trying to cross the border illegally rose at least 50 percent from 2017 to 2018, a senior Homeland Security official said Wednesday.

"Although not all gang members are affiliated with cartels, last year the Border Patrol apprehended more than 800 gang members — a 50 percent increase over the previous year," Janice Ayala, director of DHS Joint Task Force investigations, told the Senate Judiciary Committee Wednesday afternoon. There were 536 gang arrests at the border last year, and the final number for 2018 isn't known yet.

The Mara Salvatrucha gang, more commonly known as MS-13, has about 100,000 members between El Salvador, Guatemala, and Honduras, according to Ayala, and about 10,000 of them are in the U.S. DHS has arrested 8,500 MS-13 affiliates.

[Related: MS-13 gang member admits he hid in caravan to reach the US border]

U.S. Border Patrol Chief Carla Provost said transnational criminal organizations maintain heavy influence over U.S.-based gangs because they can use them to distribute drugs after they have been trafficked into the country.

Provost clarified the gang member arrests between border crossings was in addition to the 6,700 people with criminal histories who were arrested trying to enter the country between those ports.

Immigration and Customs Enforcement is responsible for deportations and homeland security investigations. The agency arrested an all-time high of 34,344 criminals in 2018.

Of that group, 3,635 people were transnational gang members who had entered the U.S. without being caught by Border Patrol or Customs and Border Protection officers stationed at ports.