Doctors Without Borders (MSF) says the security situation has dramatically deteriorated, putting its activities in Khartoum at risk.

The attackers violently assaulted a team of 18 people on Thursday as they attempted to bring supplies to the Turkish Hospital, one of only two remaining health facilities in southern Khartoum, the aid group also known as Medecins Sans Frontieres (MSF) said in a statement on Friday.

“After arguing about the reasons for MSF’s presence, the armed men aggressively assaulted our team, physically beating and whipping them,” it added.

The attackers detained the driver, threatening his life before releasing him, and stole the vehicle.

“Following this horrific incident, MSF is warning that the organisation’s activities in this hospital are now in serious jeopardy and will not be able to continue if minimum safety guarantees are not met,” the statement said.

It was unclear which, if any, rivalling faction may have been behind the alleged attack, which took place some 700 metres (0.4 miles) from the hospital.

Fighting in Sudan broke out on April 15 between the army and the Rapid Support Forces paramilitary group, driving civilians out of the wider capital region and triggering ethnically motivated attacks in the western Darfur region.

Regional and international mediation efforts have so far failed to end the conflict which has killed thousands of people and forced millions from their homes.

Those who have not fled the country have faced a severe humanitarian crisis, with scarce access to clean water, medical care and other essential services as aid groups scramble to help.

Christophe Garnier, MSF’s emergency manager for Sudan, said that “if an incident like this happens again, and if our ability to move supplies continues to be obstructed, then, regrettably, our presence in the Turkish Hospital will soon become untenable.”

MSF is one of only a few international medical humanitarian organisations still present in the capital, supporting hospitals in east Khartoum, south Khartoum and its twin city of Omdurman.

The organisation has said it has treated more than 1,600 war-wounded patients in Khartoum since the conflict began.

“Our intentions are to continue to do this,” it said in the statement. “However, the security situation has deteriorated so dramatically over the past few weeks that our presence in the Turkish Hospital is now in question.”