Darfur's most powerful rebel group signed a temporary ceasefire deal with the Sudanese government on Saturday, Chad's president says.

Idriss Deby said in a statement that the truce between the rebel Justice and Equality Movement and the Sudanese government takes effect immediately.

The Justice and Equality Movement was the most significant holdout in efforts to end the seven-year conflict in which 300,000 people have lost their lives to violence, disease and displacement.

Rebel spokesman Ahmed Hussein said a broader agreement on security arrangements and refugees will be signed within three days in Qatar, which has meditated the talks.

Besides the dead, the UN says 2.7 million people were driven from their homes in the fighting between ethnic African rebels and the government and Arab militias.