A major offensive involving 300 Sudanese government battlewagons intended to clear space for Chinese oil exploration in Darfur's far north has begun, according to rebel commanders who have come under attack.

Oil companies have been waiting for the Government to secure the region before starting work on seismic surveys.

The claims of fresh fighting come after Omar al-Bashir, the Sudanese President, embarked on a two-day peace mission to Darfur last month, promising investment and inviting rebel leaders to talks.

His visit took place days after the International Criminal Court's prosecutor accused him of genocide, murder and crimes against humanity.

Times Archive, 1916: The conquest of Darfur

The assault was given with great desperation, many of the attackers falling within ten yards of our firing line

• Conquest of Darfur completed

• Complete victory in Darfur

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Suleiman Marajan, a commander with one faction of the Sudan Liberation Army, said yesterday that the Government had lied to the world with its message of peace.

“The Government of Sudan has attacked our places with 300 vehicles. They have been here for three days protecting Chinese oil workers,” he told The Times by satellite telephone from North Darfur.

He said that “technicals” — pick-up trucks mounted with heavy machineguns — had attacked rebel positions in Wadi Atron, killing seven people. A second rebel faction told Reuters news agency that its bases had also been attacked.

No-one from the Government was available to confirm or deny the reports. North Darfur has had some of the most bitter fighting during the five-year conflict.

Many of the region's camel-herding nomadic tribes — who saw their centuries-old way of life turning to dust as the Sahara advanced from the north — answered a Government call to help to put down the rebel uprising. They formed the core of the feared Janjawid militia, which mounted a scorched earth campaign. More than 200,000 people have died since then and two million more eke out a miserable existence in aid camps.

A joint United Nations and African Union peacekeeping force has so far failed to stem the violence since being deployed at the start of the year. Ceasefire agreements have come and gone. Now a conflict defined by a lack of resources is in danger of being complicated by the most important resource of all.

Sudan is already one of Africa's biggest producers of crude oil, pumping 500,000 barrels a day. About two thirds is destined for China. Chinese companies have begun exploration in South Darfur. North Darfur lies in an oil exploration block controlled by a Saudi-led consortium and the area close to the Libyan border is thought to be the most likely to hold reserves.

Last month Ansan Wikfs, a Yemen-based firm, said that it was in talks with two Chinese exploration companies to begin seismic surveys there. However, no work could begin until the area was under Sudanese military control. No-one from the company was available to comment.

Fouad Hikmat, a Sudan analyst with the International Crisis Group, said that the offensive bore all the hallmarks of an attempt to find oil.

“The Government believes it can have development in areas where it has military control even though there is war all around. It is what they did in south Sudan during the civil war there and it appears to be what they are now doing in North Darfur,” he said.

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