An attack which killed a peacekeeper in Sudan's Darfur region last week appears to have been planned and carried out by government-linked forces, local sources in the area told AFP on Monday.

One Nigerian Blue Helmet was killed and two other peacekeepers were wounded in Friday's assault against a base of the African Union-UN Mission (UNAMID) near Muhagiriya town in southern Darfur.

Two days earlier the Sudanese government announced it had regained control of the area from rebels.

The attack "looks like it was planned and conducted by forces aligned with the government," one source said, asking for anonymity.

Local sources said peacekeepers returned fire, killing at least one of the attackers.

Sudan's army spokesman could not be reached for comment.

On Sunday the US charge d'affaires to Sudan, Joseph Stafford, condemned the attack on the peacekeepers. He told reporters it is not yet clear who carried out the "deeply troubling" assault but said security in Darfur is worsening and militias need to be disarmed.