Sessions told host Tucker Carlson that he had "no doubt" that Obama's policies led to the group's growth, saying "so many of these people are illegally here, and they came without proper authority. And with a good, lawful border, many of them would not be here."
The attorney general said that law enforcement had made progress against MS-13 until Obama took office, but "they've come back aggressively in recent years."
Sessions added that under the last administration, gang members "were directed how to enter, if they came, and claim themselves as a minor and the Obama administration let them come in the country and took them to their destination city and turned them over to some relative that claimed to be a relative."
According to Sessions, MS-13 "could qualify" as a terrorist group due to the violence of its members.
"They use machetes, they kill children, they put children into prostitution at age 12 ... They’re involved in the kinds of activities that can be identified and they can be prosecuted," Sessions said. "I believe if we stay at it, we can devastate this organization and that’s going to be our goal."