Probe sought of Libyans killed by NATO airstrikes (AP) TRIPOLI, Libya - Mohammed al-Gherari lost five family members, including a young niece and nephew, when NATO accidentally struck their compound in the Libyan capital as they slept. Nearly a year later, his grief is compounded by threats and allegations from neighbors who believe he and others who survived the attack were harboring a regime loyalist or hiding weapons for Muammar Qaddafi's forces. At least 72 civilians, a third of them under the age of 18, were killed by NATO airstrikes, according to a report released Monday by Human Rights Watch - one of the most extensive investigations into the issue. The New York-based advocacy group called on the Western alliance to acknowledge the casualties and compensate survivors. Unacknowledged Deaths: Civilian Casualties in NATO's Air Campaign in Libya (HRW) The decision by the United States and its NATO allies to launch an air campaign that mainly targeted regime forces and military infrastructure marked a turning point in Libya's civil war, giving rebels a fighting chance. But Qaddafi's government and allies in Russia and China criticized the alliance for going beyond its U.N. mandate to protect civilians. The number of Libyans killed or injured in airstrikes also emerged as a key issue in the war as Qaddafi's regime frequently exaggerated figures and NATO refused to comment on most claims, insisting all targets were military. At one point, Libya's Health Ministry said 856 civilians had been killed in NATO's campaign, which began in March 2011, weeks after the uprising against Qaddafi that erupted with peaceful protests evolved into a civil war. The U.N.-appointed International Commission of Inquiry on Libya said earlier this year that at least 60 civilians had been unintentionally killed and recommended further investigation. Based on field research conducted in Libya from August 2011 through this April, Human Rights Watch established that 28 men, 20 women and 24 children - 72 civilians in all - had been killed in eight NATO bombings in Tripoli, Zlitan, Sorman, Bani Walid, Gurdabiya and Qaddafi's hometown of Sirte. The advocacy group noted the figure was relatively low considering the extent of the seven-month campaign, which the alliance has said included 9,600 strike missions and destroyed about 5,900 military targets. It ended after Qaddafi's death in late October. But the group said it had documented several cases in which there clearly was no military target and criticized NATO for failing to acknowledge the deaths or to examine how and why they occurred. In Brussels, NATO expressed regret for any civilian casualties but said it had carried out the bombing campaign with "unprecedented care and precision" and had fulfilled the requirements of international humanitarian law.