The gang has carried out beheadings and grenade attacks in Central America and is known to hack their enemies with machetes in cities along the U.S. East Coast.

Intelligence officials warned in January that al-Qaida members have been seen in El Salvador with MS-13 members, raising concerns the gang may be smuggling terrorists into the United States.

Homeland Security Deputy Secretary James Loy called MS-13 an emerging threat to the United States, referring to the gang and al-Qaida in the same breath in testimony to Congress. Besides al-Qaida, Loy said, "We are seeing the emergence of other threatening groups and gangs like MS-13 that will also be destabilizing influences."

Local law enforcement officials are aware of MS-13's al-Qaida link.

"The terrorist aspect, especially when you think in terms of 9/11 and how intent these terrorists are, will turn the heat up on our efforts with MS-13," Boston police Detective Joseph Fiandaca told reporters at the time.

"MS-13 is the most dangerous gang in the area," he said. "They are big. They are mobile. Now they have a terrorist connection."

103 members of MS-13 were arrested on Monday, with the highest concentration coming from the New York metropolitan area.

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