A total of 6,400 security personnel were involved in what Khartoum State Interior Minister Ahmed Mohamed Haroun decribed as a "siege-and-search operation".

It was aimed at "sending a message to the enemies of the homeland confirming the capability by the police and other security agencies of protecting the safety of civilians," he told a news conference at the scene.

Haroun said police had detained 50 suspects and confiscated large numbers of "white weapons" such as knives, swords and spears.

Police chief Major General Tareq Osman al-Tahir told reporters the latest arrests brought to 88 the total detained since last Wednesday's operation in which at least 17 people died and a police station was torched.

Haroun rejected charges that the authorities were ignoring the needs of the squatters, who had been displaced from their homes in the south by the 1983-2005 civil war.

The government had always been careful to provide housing to civilians who "were forced to flock into Khartoum for reasons of war and natural disasters", he insisted.

He labelled people who spoke of the forcible relocation of the camp's residents as "plotters of intrigues for inciting sedition and disturbing security and stability."

Nonetheless the UN humanitarian mission in Khartoum was in no doubt that last Wednesday's operation was an attempt at forcible relocation and criticised what it called a heavy-handed policy.