Medics in Sudan's capital have been beaten and whipped by armed men who attacked their convoy, medical charity Médecins Sans Frontières (MSF) says.

A medical team was taking supplies to the Turkish Hospital in the south of Khartoum when it was attacked on Thursday and one of their vehicles was stolen.

Since the war erupted in mid-April, it is one of only two hospitals still operating in the south of the city.

Both are supported by MSF, which says its aid to them is now in jeopardy.

The vicious power struggle over the last three months between the army and the paramilitary Rapid Support Forces (RSF) has devastated medical facilities in the city.

'Death threats'

While more than three million people nationwide have fled their homes since April, millions of others are still stuck in Khartoum, struggling to find medicine and medical assistance.

MSF is one of only a few international aid groups still supporting hospitals in Khartoum and its twin city of Omdurman, helping to keep afloat a health system that has been under strain for decades.

It says it has treated more than 1,600 patients in these hospitals since the conflict began.

But the charity warned this might have to stop because of a dramatic deterioration in security with several incidents in which its staff had been targeted.

During the encounter on Thursday, the armed men began arguing with the 18 people in the MSF convoy made up of four trucks carrying medical supplies.

As well as assaulting the team, the armed men threatened the life of one of the drivers before releasing him and making off with one of the vehicles.

"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's Christophe Garnier said in a statement.

The confrontation took place not far from the hospital, where hundreds of patients, including those recently wounded in air strikes, are undergoing treatment.

"On a daily basis, this hospital receives around 15 war wounded patients, carries out lifesaving surgery and keeps patients with chronic diseases alive," MSF said.

According to the AFP news agency, the hospital is in an area of the city controlled by the RSF.

Aerial bombardments have intensified in residential areas of Khartoum where the paramilitary fighters have their bases, it says.

Official figures put the number of dead in the conflict at around 3,000, but it is thought to be far higher.

Some estimates from the western region of Darfur, which have seen the worst of the violence, say the death toll in one city alone is 11,000.