COLOMBO: A series of satellite images taken over Sri Lanka’s former war zone showed the existence of large grave sites and evidence of possible mortar positions near areas that had been packed with trapped civilians, a human rights group said today. The release of the images was intended to challenge government claims that the military had ceased using heavy weapons in the final months of its war against the Tamil Tiger rebels in the jungles of the north to prevent large-scale civilian deaths. UN reports show more than 7,000 civilians were killed in fighting between mid-January and May, when the military routed the remaining rebels. Rights groups accused the government of heavily shelling civilian areas and the rebels of holding tens of thousands of non-combatants as human shields. Both sides denied the accusations. Amnesty International, which called for an independent investigation into the final stages of the war, said in a statement that the analysis of satellite images from the final battlefield has identified “three different graveyards, counting a total of 1,346 likely graves.” An April 19 image of one area showed no graves, but a May 24 image showed the existence of a new graveyard with an estimated 342 graves, according to the London-based rights group. It said it was not possible to tell whether the graves hold civilians or rebel fighters. The satellite images were analysed by the American Association for the Advancement of Science. Previous satellite images of the war zone showed densely populated civilian areas that appeared to have been shelled. The new images also showed an estimated 17 mortar positions just outside a government declared “safe zone” where civilians had been told to seek refuge, Amnesty International said. Human rights groups and independent observers accused the government of repeatedly shelling the safe zone, a charge it denied. The new analysis “raises further questions about the military tactics deployed by the Sri Lankan army and the use of human shields by the Tamil Tigers,” said Christoph Koettl, an Amnesty International official. Sri Lankan defence spokesman Keheliya Rambukwella said any accusations that the government was responsible for grave sites or using mortar fire against civilians were “grossly unrealistic, biased and unacceptable.” “It’s obviously a war-torn area,” he said, adding that the rebels fired mortars of their own and may have dug the graves. Though three months have passed since the final battles, Sri Lanka still bars journalists, human rights workers and the Red Cross from visiting the former conflict zone. Meanwhile, nearly 300,000 civilians who fled the fighting are detained in military-run camps. “The fact that we are forced to rely on satellite technology to collect information about the conduct of hostilities is a pressing reminder of the urgent need for an independent investigation with unimpeded access to the area,” Koettl said. The government has rejected calls for an independent probe as a violation of its sovereignty. In May, journalists accompanied by UN Secretary-General Ban Ki-moon flew over the former battleground and saw a wasteland of scorched earth, shell craters and burned-out vehicles and tent camps.