United Nations officials announced on Wednesday that seven international peacekeepers were killed and 22 injured in an audacious day ambush by armed men in the Sudanese northern province of Darfur.

The group of about 60 soldiers and police officers was assaulted on Tuesday afternoon along a desert road area by hundreds of gunmen riding horses and others in approximately 40 vans, carrying mounted machine guns and antitank and antiaircraft weapons, Sherene Zorba, a spokeswoman for the force, said.

The attack was the deadliest on international troops in Darfur since September 2007, when 10 peacekeepers were murdered in an assail on a control center, and represented a serious shock to the United Nations and African Union peacekeeping forces that have fought harshly in order to guard civilians and the organization.

The United Nations declared on Wednesday afternoon that the deceased include five Rwandan soldiers and policemen from Ghana and Uganda. Furthermore, other 22 were wounded, seven out of which are in critical condition.

Authorities did not declare who was accountable for the attack, as it has become ever more problematic to establish who is who in the various mix of rebel movements and militia groups struggling to control Darfur. However, the sketch according to which the attackers were on horseback fiercely points out to the janjaweed militia of pro-government Arab nomads.

The new combined peacekeeping force, which was started out in January and was supported by Sudan after far-reaching negotiations, had the role of helping assure the security of civilians. Nevertheless, in spite of its initial target of 26,000 troops, it has little more than a third of that amount and most of the members are ex-soldiers of the African Union force.