The International Criminal Court (ICC) issued an arrest warrant in 2009 for Bashir to face charges of war crimes and crimes against humanity in the war-torn Darfur region. Last week it added three counts of genocide to the list of charges.

Bashir refuses to recognize the court.

"He will go to Chad tomorrow," one presidential source told Reuters on Tuesday. "He will attend the summit of the Sahel-Saharan states," the source added. Another source in the presidency said the visit would last three days.

Chad became a full member of the ICC in 2007 when relations with neighboring Sudan were at a low point. Member countries promise to cooperate with the court's investigations and the ICC can ask states to arrest suspects on their territory.

The ICC's chief prosecutor, Luis Moreno-Ocampo, told reporters last week the gravity of the new genocide charges would impel member states to arrest Bashir and deliver him to the court, which is based in The Hague.

"Implementing the warrant is the state (parties') responsibility," Moreno-Ocampo said. "It's not a past genocide, it's an ongoing genocide."

Bashir is unlikely to travel without assurances from Chadian President Idriss Deby that he will not be handed over, but some in Sudan still see the trip as risky, given the recent tumultuous relations between the neighbours.

Deby is from the Zaghawa tribe which straddles the Chad-Sudan border and there were many Zaghawa among those who rebelled against Bashir in Darfur in 2003.

Sudan's counter-insurgency campaign in Darfur used mostly Arab militia who are accused of raping, looting and murdering civilians in a bid to isolate the rebels.

Both Sudan and Chad had supported rebels trying to overthrow each other's government, but this year relations warmed and both agreed to end their support for the insurgents.

Deby stopped a Darfur rebel leader from returning to Darfur through Chad in May.