The Marine Corps has sent a team of security guards from the Corps’ embassy reinforcement team to the U.S. Embassy in Juba, South Sudan, a U.S. official said.

The Marine Security Augmentation Unit was created after the September 2012 attacks in Benghazi, Libya, that killed four Americans, including Ambassador Christopher Stevens.

The U.S. official would not say exactly how many Marines have been sent to Juba, where fighting between rival factions has killed hundreds of people recently.

“The size of the MSAU is determined based on embassy protection requirements determined by the Department of State; we will not discuss specific number,” the U.S. official said,