At least 73 people have died of mysterious causes in the Sudanese town of al-Hilaliya, besieged by the paramilitary Rapid Support Forces, the Sudanese Doctors Union said late on Wednesday.

It is one of dozens of villages that have come under attack in eastern El Gezira state since the defection of a top RSF commander to the army, which prompted revenge attacks that have displaced more than 135,000 people.

While high death tolls in other parts of Gezira came as a result of shelling and gunfire, in Hilaliya people have fallen ill with diarrhoea, overwhelming a local hospital according to the union and three people from the area.

A network blackout enforced by the RSF has made it difficult to determine the exact cause.