At least 40 people were killed and dozens injured Sunday in air strikes on a neighbourhood in the south of Sudan's capital Khartoum, a local group said.

"At about 7:15 am (0515 GMT), military aircraft bombarded the Qouro market area," said the local resistance committee, one of the groups that used to organise pro-democracy protests and now provides assistance during the war.

"A preliminary count indicates that 40 deaths and dozens of wounded arrived" at Bashair hospital, the committee said.

The hospital meanwhile issued an "urgent appeal" for all medical professionals in the area to come and help treat the "increasing number of injured people arriving".

Since April 15, Sudan has been gripped by a devastating war pitting the regular army against the paramilitary Rapid Support Forces.

Nearly 7,500 people have been killed in nearly five months of fighting, according to a conservative estimate from the Armed Conflict Location & Event Data Project.

The real death toll is presumed to be much higher as access to many areas have been cut off completely and the warring sides have not declared their losses.

The fighting, concentrated mainly in Khartoum and the western region of Darfur, has also forced nearly five million people to flee their homes, according to the United Nations.

Multiple international efforts have failed to mediate a ceasefire in the conflict.