A bomb has hit the residence of the Saudi ambassador to Chad, killing the wife and daughter of an embassy staffer taking shelter from the fighting between the government and rebel forces.

The official Saudi press agency quotes an unnamed foreign ministry official as saying that all members of the Saudi mission to Chad in N'Djamena had gathered with their families at the ambassador's home, as they waited to be evacuated because of the violence.

This incident coincides with a day of fierce fighting between government forces and rebels who entered the capital earlier Saturday.

A French military official reports that the Chadian army has pushed the rebels back from the presidential palace, although the fighting is continuing and the situation remains uncertain. Rebels earlier had claimed to have taken control of the city.

Both sides say there has been looting in the capital.

At the African Union summit in Ethiopia, the AU chairman, Tanzanian President Jakaya Kikwete, said if the rebels are successful in toppling Chad's government, they will not be recognized by the pan-African organization.

A UN spokesman in Geneva, William Spindler, says the fighting has prompted the U.N. to withdraw its remaining staff from N'Djamena. On Friday, 51 non-essential staff were pulled out.

The U.S. Embassy in N'Djamena says it is evacuating selected employees and their families.

The Chadian rebels began advancing on the capital Monday. They have said their aim is to overthrow President Idriss Deby if he will not accept a power-sharing government.

President Deby has been in power since 1990. Several years ago he changed the constitution to allow unlimited presidential terms. His rule has been marked by allegations of corruption and lately by defections from his inner circle to rebel movements.

Some information for this report was provided by AFP, AP and Reuters.