(Adds details, donors conference, prisoner release)
DOHA/KHARTOUM, Feb 11 (Reuters) - The Sudanese government signed a Qatar-sponsored ceasefire with a splinter Darfur rebel group, Sudanese and Qatari state media said, in an attempt to revive a stalled peace process to end a decade-long conflict.
The deal was signed by a group that calls itself the Justice and Equality Movement (JEM) but which is a tiny off-shoot of the main rebel group of that name.
News of Sunday's agreement follows a recent upsurge in fighting in Darfur, a region the size of Spain where rights groups and the United Nations say 300,000 people may have died since the conflict began in 2003.
The government says the death toll is about 10,000.
Qatar brokered a 2011 peace deal between Sudan and the small Liberation and Justice Movement (LJM), and hopes the latest accord will inject new life into peace efforts.
The 2011 deal promises development aid from donors including Qatar, which will host an April 7-8 donor conference, Qatari Deputy Prime Minister Ahmed bin Abdullah al-Mahmoud told the official Qatar News Agency.
Qatar hopes the forum will persuade more rebels to join the peace process and choke off support for groups who refuse to lay down their weapons.
A surge in fighting between rebels and government soldiers, as well as between the region's various tribes, has displaced more than 130,000 civilians since late December, according to the United Nations.
More than 1.4 million people already live in camps across Darfur, according to the U.N.
Diplomats say Western donors will only contribute funds in Doha if security improves in Darfur and if Sudan fulfils its part of the 2011 deal such as co-funding an authority to run the region and disarming pro-government militias.
The International Criminal Court has issued arrest warrants for President Omar Hassan al-Bashir and other senior Sudanese officials on charges of war crimes and genocide in Darfur - accusations the Sudan dismiss as politically motivated.
Conflict also stalks Sudan's border with South Sudan, the territory that seceded from the north under a 2011 peace deal that ended decades of civil war in the giant African state.
The two neighbours came close to a return to full-scale war over territory and oil payments when border fighting escalated in April, but they agreed to defuse tensions in September.
On Monday, Sudan released five South Sudanese soldiers it captured last year along their disputed border, the International Committee of the Red Cross (ICRC) said. Both sides have accused the other of holding an unspecified number of prisoners. (Reporting by Ali Abdelatti in Cairo, Sami Aboudi in Dubai and Ulf Laessing in Khartoum; Editing by Jon Boyle)