MAZAR-I-SHARIF (Reut-ers/AFP) - Nato troops killed six civilians during a night raid on a house in northern Afghanistans Sar-e Pul province late, the provincial governor told Reuters. The Nato-led force said soldiers on a joint operation with Afghan troops had killed five men who were armed and opened fire on them. They are investigating the identity of the dead men, a spokesman said. Afghans are allowed by law to own guns, and in rural areas many do, to protect against threats from bandits, militias or rivals with weapons. Critics of night raids say people confused at being woken from sleep may open fire on troops who arrive under cover of darkness, even if they have no insurgent links. Meanwhile, fresh protests erupted in Kabul over the burning of Holy Quran by a US pastor, taking angry and violent demonstrations into a fifth day, an AFP photographer said. Several hundred people gathered at Kabul University chanting death to America and we want the burner of the Holy Quran to be tried in the wake of previous protests which have left 24 people dead, including seven UN staff. A protest has started by Kabul University students in front of the university. It is peaceful and under control at the moment, interior ministry spokesman Zemarai Bashary told AFP. The protesters were contained within the university campus by heavy police deployments and all roads leading in and out of the university were blocked, the AFP photographer said.