HASKANITA, Sudan, Oct 29 (Reuters) - Camouflaged soldiers from Darfur's largest rebel group marched on Saturday to open a congress intended to unify a movement whose disarray has fuelled fresh violence and hampered relief efforts and peace talks.

"These are the people who taught the regime in Khartoum lessons in no less than 100 battles," Seifeddin Haroun, an organiser, said as leaders of the Sudan Liberation Army (SLA) met in a huge tent in the middle of Darfur's eastern desert.

Heavily armed troops and truckloads of young dreadlocked guerrillas provided security while up to 10,000 white-clad men and brightly dressed women surrounded the tent.

"SLA, SLA for liberation," delegates chanted. "Revolution! Freedom! Liberty!"

A brass band played and SLA Secretary-General Minni Arcua Minnawi and Commander-in-Chief Juma'a Haggar inspected troops in front of the cheering crowds, many of whom had traveled for days through hostile territory to attend the meeting.

"Victory, victory to Haggar we are with you to liberation," members chanted.

Tens of thousands have been killed and more than two million chased from their homes during a 2-1/2-year revolt by

mostly non-Arab rebels in Darfur. They accuse the Khartoum government of monopolising power and wealth. Around 200,000 refugees fled to Chad.

"The choice to negotiate is the first choice for us, but the choice of war is the last choice," Minnawi told the congress.

CALL FOR UNITY

The SLA congress, the first of its kind, aims to democratise the movement. Several hundred delegates were to elect a leader, discuss a new constitution and outline the SLA's position at African Union-sponsored peace talks in Nigeria's capital Abuja.

"We hope that this conference will come out with a decision for unity so we can face this regime in a more organised way," Minnawi said.

SLA President Abdel Wahed Mohamed el-Nur and Minnawi are barely on speaking terms and the SLA rank and file called the congress to unite the leadership in the hopes it would inject new life into the stalled Abuja talks. The last round failed because of their divisions.

The conference organisers waited two minutes for Nur, or a representative, to give a speech but no one came forward.

"According to the principles of democracy, we have given the chance to the president to speak but as yet he has not arrived," Haroun said.

Minnawi said it was not too late and urged Nur to come, who returned to Darfur for the first time in more than a year a few days ago.

"We call him to come and will continue to call him until the congress is over," Minnawi said.