KHARTOUM, Sudan - United Nations officials say seven UN-African Union peacekeepers were killed and 22 others wounded in an attack Wednesday in Sudan's Darfur region.

UN Secretary-General Ban Ki-moon's office says at least seven of the wounded are in serious condition.

Five Rwandan soldiers and two police officers, one from Ghana, the other from Uganda, were killed.

A spokeswoman says the secretary-general "condemns in the strongest possible terms this unacceptable act of extreme violence'' against peacekeepers.

The office says the attack came when a joint police and military patrol investigating the killing of civilians in North Darfur was ambushed by unidentified militia.