Muhammad Ahmad Abd al-Gadir Arbab, a lawyer and spokesman for the people of Soba Aradi, said the armed forces sealed off the entire area, about 30km south of the Sudanese capital Khartoum, on Tuesday.
"We are surrounded since this morning and are waiting to see if they will start something again," said one camp resident, who declined to be named.
Clashes erupted last week when Sudanese police tried to relocate refugees, mainly from southern Sudan, away from the camp.
Officials said most of the victims died as crowds massed around the police station and burned it down.
Both camp residents and police officers were among the victims.