Darfur rebels suspended formal peace talks in Nigeria on Monday to put pressure on the government to halt an offensive in the vast desert region, delegates said. Rebel negotiators said they would not leave the Nigerian capital Abuja immediately, and were still open to informal consultations, but that the formal talks would not resume until the situation on the ground improved. "We are suspending the talks until the situation has changed and there is a clear commitment that the Sudanese government will stop the offensive," said Bahar Ibrahim, a member of the rebel Sudan Liberation Movement. "We are still open to consultations -- talking to people -- but we will not be attending the meeting," he added. The African Union, which is mediating the talks, said attacks had tripled in frequency since September and were now occurring daily in Darfur, where about 1.6 million people have been driven from their homes. The 53-member pan-African body blamed both sides for violating a ceasefire, but said they were working to keep the rebels at the talks, which are trying to seek a political agreement after earlier deals on aid and disarmament. "There is no justification for a suspension," said African Union chairman Sam Ibok. The government also urged the rebels to stay at the conference which began on Friday. "Only negotiations and talks will solve the problems," said government spokesman Ibrahim Mohammed Ibrahim. The African Union had set a Dec. 22 deadline to conclude talks on a declaration of principles including power sharing, wealth sharing, security, demobilisation and reintegration.