A helicopter and its crew contracted by peacekeepers in Sudan's Darfur have been "detained" be rebels in the troubled region for 10 days, the mission said on Tuesday.

The Mi-8 chopper was contracted by a Russian company and did not carry UN markings, Christopher Cycmanick, acting spokesman for the African Union-UN Mission in Darfur (UNAMID), told AFP.

One of the crew members is Sudanese while the other two are foreign, he said, without giving their nationality.

The helicopter was delivering supplies to UNAMID locations in South Darfur state when a mechanical failure forced it to make an emergency landing on August 3, southeast of Nyala city, Cycmanick said.

"The crew members, a total of three, were detained by members of SLA-Minni Minnawi," he said, referring to one of Darfur's main rebel groups.

"Since that time, communication has been maintained with all parties and negotiations have been underway for gaining the safe release of the crew as well as the recovery of the helicopter," Cycmanick said.

Hussein Minnawi, a member of the Minnawi group's political bureau, told AFP that an investigation was underway to determine if the chopper was owned by a private firm or the government.

"I think if it is a private (helicopter) then it will be released," he said. "We are in conflict with the government, not private" firms.

The aircraft landed west of Ed Daein town, where separate attacks on Monday hit a UNAMID police patrol on Monday in a region where the Arab Rezeigat and Maaliya tribes have been fighting.

"The situation in the area is still tense," Cycmanick said, adding there were no injuries among peacekeepers, contradicting an earlier UN report.

Inter-ethnic fighting has been the major source of violence in Darfur this year, where an estimated 300,000 people were displaced in the first five months alone, UNAMID says.

These battles reflect the altered dynamics of a decade-old conflict in which, observers say, the government can no longer control its former Arab tribal allies known as Janjaweed.

With the situation changing, the United Nations Security Council called last month for a review of the UNAMID mission, which has encountered criticism that it has not used its full powers to counter the upsurge of violence.

UNAMID was set up in 2007 under Chapter VII of the UN Charter, which allows for the use of armed force and mandated to protect civilians and provide security for aid workers.

"While the protection of civilians is at the heart of UNAMID the mission does not become a party to the conflict," whether tribal or between the government and rebels, Cycmanick said.

"We do not take sides and we are impartial," he said, adding the government has primary responsibility for protecting the people.

Non-Arabs in Darfur began a rebellion 10 years ago against what they saw as the domination of Sudan's power and wealth by Arab elites.

In response, the government-backed Janjaweed militia shocked the world with atrocities against them.

Tribal disputes have been driven by conflict over resources including land, water and mineral rights, observers say.

Prior to this year's surge of violence, there were already 1.4 million people in camps for those uprooted by Darfur's conflict.

President Omar al-Bashir is wanted by The Hague-based International Criminal Court for war crimes, crimes against humanity and genocide allegedly committed in Darfur.

...,/.,