Fighting in the Sudanese capital raged into the early hours of Sunday after a day of deadly battles between the Rapid Support Forces (RSF) and the army that left at least 56 people dead and nearly 600 wounded. Explosions and gunfire rang out on the deserted streets of Khartoum, according to witnesses, after the RSF said they were in control of the presidential palace, Khartoum airport and other vital facilities. The army denied the claims, and in a statement late Saturday, the Sudanese air force urged people to stay indoors as it continued air strikes against bases of the RSF. Fighter jets were earlier seen flying overhead. The Sudanese Doctors' Union reported at least 56 civilians had been killed and 595 people, including combatants, had been wounded since the fighting erupted on Saturday. Scores of military personnel were also killed, it said without giving a specific number due to a lack of firsthand information from many of the hospitals where those casualties were taken. The group earlier said it recorded deaths at Khartoum's airport and Omdurman, as well as west of Khartoum in the cities of Nyala, El Obeid and El Fasher. The clashes follow rising tensions over the RSF's integration into the military. The disagreement has delayed the signing of an internationally backed agreement with political parties on a transition to democracy.