A Sudanese employee of the World Food Programme, his wife and two children were among the casualties, a spokeswoman for the UN agency said on Friday.

An investigation was underway to determine the cause of the crash, though there were no immediate reports of foul play, the statement added.

The town of el-Geneina, the capital of West Darfur which lies close to Sudan’s border with Chad, has recently witnessed clashes between Arabs and non-Arabs that killed dozens of people, including women and children.

An international peacekeeping mission said on Friday that at least 65 people were killed in the violence over the past week, while more than 50 others were wounded.

The joint African Union-United Nations peacekeeping mission in Darfur, UNAMID, said it was deeply concerned by the "deterioration of the security and humanitarian situation in el-Geneina and the surrounding area".

Sudan's Red Crescent said  that more than 8,000 families were displaced after violence erupted in the region.

The clashes pose a challenge to efforts by Sudan's transitional government to end decades-long armed campaigns in areas like Darfur. In response, rebel groups from Darfur suspended peace talks with the government and called for an investigation.

Earlier this week, Sudanese Prime Minister Abdalla Hamdok and General Mohamed Hamdan Dagalo, deputy head of the Sovereign Council, had visited the town and expressed their commitment to prosecuting the perpetrators.

Plane crashes are not uncommon in Sudan, given the country's poor aviation safety records.

In 2003, a civilian Sudan Airways plane crashed into a hillside while trying to make an emergency landing, killing 116 people, including eight foreigners. Only a small boy survived the Boeing crash.