KHARTOUM - A senior Darfur rebel leader accused the Sudanese government on Wednesday of trying to grab land ahead of October peace talks, and threatened to pull out of the negotiations unless attacks stopped.

Justice and Equality Movement (JEM) leader Khalil Ibrahim said the violence in the remote west would make it impossible for him to travel to negotiations with Khartoum, due to take place in Libya on Oct. 27.

"The government is escalating its attacks. There are daily attacks," he said. "They are killing civilians and animals and there are displaced people. They are trying to take as much land as possible before the peace talks and the arrival of peacekeeping troops."

A JEM field commander said government aircraft had bombed villages close to a rebel-held town in north Darfur on Tuesday, killing six civilians. A Sudanese army spokesman denied the army was escalating attacks and accused rebels of starting the fighting in Haskanita by ambushing government forces.

Ibrahim said if the fighting persisted it would be impossible to attend the talks, adding: "There is a war going on and we would have to fight for our survival."

He said he was calling on the United Nations to step up its pressure on the Sudanese government to stop attacks in Darfur.

Khartoum signed a joint statement with the United Nations last week agreeing to end violence in Darfur, prepare for peace talks with rebel leaders in Libya, and help in the deployment of 26,000 U.N. and African Union peacekeepers in Darfur.

The reports of fresh violence on Tuesday came on the heels of fighting in Haskanita that the African Union said involved use of heavy weapons including helicopter gunships on Monday.

REBELS: SIX CIVILIANS KILLED

JEM field commander Abdel Aziz el-Nur Ashr said six civilians were killed on Tuesday in bombing raids on villages near Haskanita, and a JEM statement asked aid groups to help bury 500 to 600 government soldiers it said were killed in a failed ground attack on Haskanita after an aerial bombardment.

The Sudanese army spokesman dismissed the rebel report on army casualties as an exaggeration, and blamed the rebels for the violence. He said the army had been ambushed and was then forced to call in air support as backup.

"It was a hostile action by the rebels," he said, speaking on condition of anonymity. "There were casualties on both sides. The situation remains unstable."

Reports from rebel groups of the numbers of casualties and prisoners taken during that fighting have varied widely.

U.N. spokeswoman Radhia Achouri said hijacking of aid vehicles by militias and other groups in Darfur was "continuing at an alarming rate".

Three displaced people were kidnapped and killed in south Darfur's Kalma camp on Saturday. On Sunday, 20 women from Al-Hamidya camp in west Darfur were detained by an Arab militia as they went to collect firewood but were later released.

Meanwhile, ailing senior Darfur rebel figure Suleiman Jamous, the Sudan Liberation Movement's humanitarian coordinator, said he had finally received a passport and exit visa and would leave the country for medical care as soon as the United Nations could arrange a flight.

International experts estimate 200,000 people have died and 2.5 million have been driven from their homes in the past 4-1/2 years of violence in Darfur, fuelled by ethnic and political conflict. Khartoum says 9,000 have died.