"I'm hereby requesting approval to meet the request of the African Union to supply one company of Nigerian troops as part of the AU protection force in Darfur," Obasanjo said in a letter read out to the Nigerian senate.

"This approval should equally make allowance for the Nigerian contribution to be expanded as may be necessary to one battalion, but not more than two battalions at the utmost," he added.

A Nigerian army infantry battalion is around 770 strong. Officials had previously said that the vanguard comapny and one battalion would link up in Darfur with the same number of Rwandan troops to make up a force of 2,000.

Sudan has welcomed the deployment of the initial two companies, who would essentially be used to protect African Union observers, but it is not yet clear on what terms a larger force could be deployed.

More than 50,000 people have been killed and more than a million put at risk of starvation or ethnic violence since fighting erupted between Darfur's rebel movements and pro-government forces last year, according to the UN.

Khartoum stands accused of arming a brutal militia, the Janjaweed, and sending it to kill civilians from tribes thought to sympathise with the rebels.

The African Union, of which Obasanjo is the current chairman, has invited the parties to a peace conference in Abuja on Monday and has offered to send soldiers to oversee the distribution of aid and the start of a peace process.

WAR.WIRE