Armed men shot dead seven people and injured 20 in clashes at a refugee camp in Sudan's Darfur region on Saturday, peacekeepers said, in a sign of mounting violence in and around the area's displacement centres.

Darfur's joint UN/African Union (Unamid) peacekeeping force said gunfire broke out at the Hamidiya camp, close to the town of Zalingei in West Darfur state, on Saturday morning.

More than seven years of fighting in the arid region has driven more than 2 million to take shelter in ramshackle camps that are dependent on aid agencies for food and water.

Many camps have become highly politicised and Khartoum has accused some camp leaders of stockpiling weapons and harbouring fighters for rebel groups who took up arms against the government in 2003.

'Seven people were killed in the IDP (internally displaced people) camp and at least 20 were injured. We don't know who was behind it,' said Unamid spokesman Chris Cycmanick.

The clashes came two days after rebels said pro-government fighters killed up to 54 people at a market in North Darfur's Tabarat village. Most of the reported victims were residents of a nearby refugee camp.

Unamid said the insurgent Sudan Liberation Army (SLA) had allowed a platoon of peacekeepers to visit the area around Tabarat on Saturday to check the details of the attack.

There has also been growing tension in Kalma camp, home to up to 82,000 people outside the capital of South Darfur State Nyala.

Khartoum is demanding Unamid hand over six Darfuris it accuses of instigating clashes in Kalma in late July that killed at least five people. Unamid has refused to do so without seeing evidence of their crimes and guarantees that they will have a fair trial. – Reuters