Sudanese President Omar al-Bashir, right, is greeted by a supporter during a conference in Khartoum on Wednesday. (Abd Raouf/Associated Press)Sudanese President Omar al-Bashir, facing a possible indictment by the International Criminal Court for alleged war crimes in Darfur, announced a ceasefire in the region on Wednesday.

But a key Darfur rebel group, the Justice and Equality Movement (JEM), said the announcement was not serious and vowed to fight on until it secured assurances from the government that it would share power and wealth more equitably.

Bashir, accused in July by the ICC chief prosecutor of masterminding a campaign of genocide in Darfur, said his government would launch an immediate campaign to disarm militias in the vast area in Sudan's west.

"I hereby announce our immediate unconditional ceasefire between the armed forces and the warring factions, provided that an effective monitoring mechanism is put into action and observed by all involved parties," Bashir said in a speech.

Suleiman Sandal, the deputy general commander of JEM, told Reuters in an interview by satellite phone: "We cannot cease fire for free."

The ceasefire was recommended by the Sudan People's Forum — a platform of government and opposition figures. Darfur rebels have boycotted the forum.

The president, however, did not promise to release political prisoners from Darfur, another recommendation by the forum.

International experts estimate that 200,000 have lost their lives and 2.5 million have been displaced since the Darfur conflict flared in 2003, when mostly African rebels revolted against the Khartoum government, charging it with neglect.

The government puts the death toll at 10,000 people.

With files from Reuters