As heavily armed gangs continue to challenge Haiti’s weak government and turn the country’s capital into a battlefield, the State Department on Sunday flew in U.S. Marines to reinforce its embassy and evacuate non-essential personnel.

The middle-of-the-night operation was conducted via helicopter by the U.S. military at the request of the State Department, the U.S. Southern Command said in a statement.

“This airlift of personnel into and out of the embassy is consistent with our standard practice for embassy security augmentation worldwide, and no Haitians were on board the military aircraft,” the statement said.

The airlift comes amid ongoing gang attacks in multiple locations around metropolitan Port-au-Prince, including Tabarre, where the U.S. embassy is located. Several nearby businesses have been looted and overtaken by armed gangs that today control more than 80% of the capital.