Protesters burn tyres during a demonstration against a report of the Attorney-General on the dissolution of the sit-in protest in Khartoum. File picture: Mohamed Nureldin Abdallah/Reuters

Khartoum - Four school children and one adult were killed by unknown snipers during an anti-government protest in central Sudan, a doctors' association said Monday.

Dozens of others were injured, some of them critically, when a group of secondary school children were peacefully protesting against the ruling Transitional Military Council in the town of El Obeid in North Kordofan State, the Central Committee of Sudan Doctors (CCSD) said in a statement.

The identity or affiliation of the snipers remained unclear on Monday.

Anti-government demonstrations began in the volatile East African nation late last year with protesters calling for long-time leader Omar al-Bashir to go.

The military stepped in in April, launching a coup and arresting him.

But protesters have argued that the new military rulers are a continuation of al-Bashir's former regime and have sought more concessions and a transition to civilian government.