Mohamed Ahmed Abdel Gader Arbab, a lawyer and spokesman for the people of Soba Aradi, said the armed forces have sealed off the entire area, about 30 km (19 miles) south of the Sudanese capital Khartoum.

"They have cordoned off all areas and have taken tough measures to stop people leaving," he said.

Clashes erupted last week when Sudanese police tried to relocate refugees mainly from southern Sudan away from the camp. Both camp residents and police officers were among the victims.

Officials said most of the victims died as crowds massed around the police station and burned it down.

Officials said most of the victims died as crowds massed around the police station and burned it down.

Slums and camps surrounding the sprawling capital are home to more than 2 million people, mostly southerners displaced by two decades of civil war.

The slum areas around Khartoum have little or no running water or electricity and aid agencies have found it difficult to improve the situation there.

Khartoum authorities say they want to demolish the slums to relocate residents to permanent, planned housing plots.