U.S. Deputy Secretary of State William Burns, the most senior U.S. official to visit Libya since a deadly 2012 attack on a U.S. compound there, said on Thursday, April 24, that Libya was facing a severe challenge from an increase in extremist violence.

"Rising violent extremism is an enormous challenge first for Libya but also for Libya's international partners," he told a news conference after talks in the capital Tripoli, according to Reuters.

Washington recognized the severity of that threat, he added.