Attackers who killed seven peacekeepers in Sudan’s Darfur were armed with anti-aircraft guns, the head of the African Union-UN mission said, calling for a review of whether his men have the tools to deal with worsening insecurity.Saturday’s ambush left seven Tanzanian troops dead and wounded 17 other military and police personnel from the African Union-United Nations Mission in Darfur (Unamid)."They had RPGs. They had AK-47s and they apparently even had anti-aircraft guns,” Unamid chief Mohamed Ibn Chambas told AFP after inspecting the patrol’s bullet-damaged vehicles – including a marked ambulance."So they were well-armed and they came in about 10 vehicles,” he said, citing preliminary reports. Chambas spoke on Sunday after returning from Khor Abeche, where the ill-fated patrol was based north of the South Darfur state capital Nyala.It was the worst attack in Unamid’s five-year history."We are all very saddened by it,” Chambas said.Another marked Unamid ambulance was shot up earlier this month in an attack that wounded three Nigerian peacekeepers east of Nyala.Critics have said Unamid is not aggressive enough in fulfilling its mandate to protect civilians.Unamid was set up in 2007 under Chapter VII of the United Nations Charter, which allows for the use of armed force.Last month Chambas told AFP that the mission, "frankly, is not deployed in the posture of a Chapter VII,” as it does not have helicopter gunships or other combat elements. Neither does it have "a clear mandate to be able to go after the spoilers,” he said at the time. It has instead focused on negotiations, trying to secure a comprehensive peace agreement for the region, he said.Asked on Sunday whether he would now seek more powerful weaponry or gunships for Unamid, Chambas said the mission’s senior military and police will have to decide.Darfur’s rebels accused government-linked militiamen of staging the ambush but Khartoum blamed the insurgents."They are doing this in order to frighten Unamid and to shake the international community in order to withdraw this force,” Abdel Wahid Mohammed al-Nur, who commands a faction of the Sudan Liberation Army (SLA), told AFP.Sudan’s foreign ministry condemned the incident, expressed condolences to the victims’ families, and blamed "the so-called Sudan Liberation Army Minnawi faction... for this aggression”.Abdullah Moursal, spokesman for the SLA group led by Minni Minnawi, said: "We don’t have any doubt that the act was done by government militia... This area is completely under government control.” Chambas said he would not speculate on the motives for the attack or who was behind it.A Unamid board of inquiry has been struck to investigate, as is standard procedure.