Sudan's army has begun a massive operation to wipe out rebel bases in Darfur's far north, two Darfur rebel factions said on Wednesday.
The army attacked with more than 200 vehicles in Wadi Atron, near the Sudanese-Libyan border on Tuesday and took control of areas which had for years been under the control of rebels who want more autonomy for the region.
"They came with more than 200 vehicles and killed seven people," commander Suleiman Marajan told Reuters from Darfur. He is from the Sudan Liberation Army (SLA) faction led by founder Abdel Wahed Mohamed el-Nur.
"They attacked our areas in Wadi Atron with a massive force," said al-Sayyid Sherif from the rival Sudan Liberation Army (Unity) faction.
"We consider this a new declaration of war."
The army spokesman declined to immediately comment. One army source confirmed there were operations under way but could not give details.
Marajan said the government had moved in Chinese workers who were looking for oil in the remote area.
North Darfur is part of Sudan's oil Block 12A operated by a consortium led by the Saudi Arabian company al-Qahtani. Chinese companies dominate Sudan's budding oil sector which produces more than 500,000 barrels per day of crude.
Sudan's Oil Ministry could not immediately confirm whether any exploration has begun in Block 12A.
The North Darfur operation follows a rare visit to Darfur by the minister of defence and the head of the intelligence services last week.
Unity is one of the largest Darfur rebel groups and was one of the few factions to say they were ready to go to peace talks. A joint U.N.-African Union mediator has been appointed and was expected to take up his new position on Aug. 1, based in Darfur.
Djbril Bassole from Burkina Faso, a Francophile, is having intensive English lessons before he moves to Darfur and his new post. He also speaks no Arabic.
Both rebels and the government have attacked each other trying to gain territory ahead of previous Darfur peace talks.
International experts estimate some 200,000 people have died and 2.5 million driven from their homes since mostly non-Arab rebels took up arms in early 2003 accusing central government of neglect.