The Sudanese government has repeatedly violated its ceasefire agreement with rebels in Darfur by bombing villages across the region, aid agencies and peace monitors said January 27.

The accusation came just days after the United Nations said renewed fighting in the region had killed at least 100 people and displaced more than 9,000.

The latest reports from sources within aid agencies working in Sudan said the government had bombed the village of al-Malam in North Darfur state. The African Union (AU), which has troops in Darfur to monitor the ceasefire, said it was investigating the claim.

Aid workers also said Arab militias known as Janjaweed attacked a village in South Darfur state, killing three people.

The AU said it had further reports of Khartoum aircraft bombing the South Darfur village of Shangil Tobaya, 40 miles south of El-Fasher.

Al-Malam, on the border between North and South Darfur, is an area the government said rebels attacked this week. Khartoum accused the rebels of burning eight villages and killing dozens of people. The rebels deny the charges. Jean Baptiste Natama, an AU political officer, said his forces were investigating the incident.

As the ceasefire violations continued, the UN envoy to Sudan, Jan Pronk, called on January 27 for the immediate release of three Sudanese employees of an International Christian aid agency who were abducted last month in South Darfur.

The workers, well-drillers of the Adventist Development and Relief Agency International, were captured at gunpoint on 16 December, according to the aid agency.

Mr Pronk said the responsible groups would "be held accountable for their acts".

"Humanitarian workers who have come to help victims of violence should not themselves become targets of such violence," he said.

With little sign of a breakthrough to bring peace to the region, the United States is making several proposals to the UN Security Council to bring perpetrators of atrocities in Darfur to justice.

The US last year called the violence in Darfur a genocide and has played a leading role in trying to punish those responsible.

United States spokesman Richard Grenell said ideas would involve using methods other than the International Criminal Court, a body the US opposes. That would almost certainly put Washington in conflict with European leaders, who back the court.

The developments come as a UN commission is preparing to deliver a report examining the Darfur situation to see whether the crisis there is indeed a genocide. US officials have said privately they do not expect the report to make that determination.

This week the five permanent members of the UN Security Council - Russia, China, France, Britain and the US - to discuss action on Sudan.