Explosions rocked the airport and port at Sudan’s main coastal city on Tuesday, the latest escalation in two years of conflict between the North African nation’s army and the Rapid Support Forces militia.

Sudan’s wartime capital was struck by a series of explosions on Tuesday as the paramilitary Rapid Support Forces sought to use drones to expand the conflict deep into army-controlled territory. The Red Sea city of Port Sudan became the de facto capital after the Sudanese armed forces were driven from Khartoum during a power struggle with erstwhile allies from the RSF two years ago.