Sudan's air force has carried out new bombing raids against two rebel areas of Darfur province, the African Union says.
The fresh attacks on Saturday threatened to de-rail a peace deal between Sudan and the Sudan Liberation Army (SLA), the main rebel group, the AU said in a statement on Sunday.
The bombings came just a day after African Union (AU) officials visited the area on Friday to secure their commitment to a ceasefire, Luke Aprezi, commander of a 7,000 strong AU force in Darfur said.
One rebel group confirmed the attack, but did not say much damage had been caused.
"For the first time, I visited them [rebels] in the field in Um Rai [North Darfur] ... and I was able to get a ceasefire commitment from them," Aprezi said.
"Unfortunately [Sudan's army] went and bombed the area and it looks like I led them to the area to get bombed."
The meeting was held on Friday and he notified the government of it, he said.
Aprezi's AU force, hampered by lack of equipment and funds, has struggled to stem the violence in remote western Sudan.
Peace deal
A peace deal was signed between one of three negotiating rebel factions and the government in May.
Rival rebel groups rejected it, formed a new military alliance and renewed hostilities with the government.
A government army spokesman said there was no confirmation of this in Khartoum.
"Darfur commanders cannot undertake bombing operations without the knowledge of central command in Khartoum," the spokesman told Reuters news agency.
"But we in central command are completely committed to the ceasefire."
Following the new bombings, it was unclear if rebel groups would honour the ceasefire negotiated by Aprezi on Friday.
The fighting has driven 2.5 million people from their homes and killed an estimated 200,000.