The Justice and Equality Movement (JEM), a key rebel group in Darfur, said on Wednesday a ceasefire announced by the Sudanese government was not serious, reported World buletin.
Suleiman Sandal, the deputy general commander of the group, told Reuters JEM would not stop fighting government forces in the region until a "framework deal that would guarantee the movement's rights is reached."
"We cannot cease fire for free," he said.
Sudanese President Omar Hassan al-Bashir announced on Wednesday an immediate and unconditional ceasefire in the Darfur region of western Sudan.
Bashir said the government would also disarm the militias in the region.
"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.
The ceasefire was recommended by the Sudan People's Forum -- a platform of government and opposition figures. Darfur rebels have boycotted the forum.