By Andrew Heavens

KHARTOUM (Reuters) - Sudanese forces on Sunday launched fresh attacks on a base held by Darfur rebels who signed a 2006 peace deal with the government, the faction's leader said.

Minni Arcua Minnawi, leader of the Sudan Liberation Army group, said he did not know why his headquarters in the East Jabel Marra area was attacked on Saturday and Sunday.

The rebel leader, who became a presidential assistant under the 2006 Darfur Peace Agreement, said he was closing his office in Sudan's presidential palace in protest.

No one was available from Sudan's armed forces to comment.

Other rebels say the fighting is the latest in a string of assaults on their positions in North Darfur over the past week.

Sudan has stepped up diplomatic efforts to suspend a move by the International Criminal Court to indict its president for genocide and other war crimes in Darfur.

More than 200,000 people have died since rebels from the remote western region took up arms against the government in early 2003, say international experts.

Khartoum mobilised mostly Arab militia fighters to quell the revolt and now stand accused of widespread atrocities. Khartoum puts the death count at 10,000 and says the western media exaggerates the conflict.

"They attacked us last night and they attacked us again this morning," said Minnawi. "Both times we defeated them ... I do not know why the government troops are attacking us. This is how the government of Sudan behaves."

DIRECT ATTACK

He said the base close to the town of Tabit, about 50 km (30 miles) south west of North Darfur's capital El Fasher, was attacked by government troops and allied militias, adding it was too early to estimate casualties.

Areas controlled by Minnawi's fighters have been attacked by government troops in the past. But the leader's Khartoum-based chief of staff Mohamed Bashir Abdullah said it was the first time the army had launched a direct attack on his men.

Minnawi left Khartoum and moved to another base in Darfur three months ago, saying he would not return until the Sudanese government found the will to implement the 2006 deal.

Abdullah said he had now received orders "to close down the office at the presidential palace and deliver the keys to the palace authorities".

He said Minnawi would keep his position as a presidential assistant and remain a signatory to the Darfur Peace Agreement. The office closure was a "symbolic protest" but Sunday's attacks marked a "turning point" in the group's relationship with the government, he added.

Leaders from three other rebel groups confirmed the attacks near Tabit and reported other clashes with government forces across North Darfur on Sunday.

"Bombing has been continuing up to now," said Sherif Harir from the Sudan Liberation Army's Unity wing, saying more than a week of ground and air attacks had forced residents to flee 20 villages in the remote area.

Harir said Unity fighters had killed more than 200 soldiers and forced the government troops to retreat to El Fasher and the town of Tawila. The figures could not be verified independently.

Reports of the fighting in the region were confirmed by commanders from the SLA faction led by Abdel Wahed Mohamed el-Nur and the insurgent United Resistance Front.

An army spokesman on Saturday said troops had entered the area to arrest armed bandits but did not mention any clashes.

(Editing by Janet Lawrence)