The naked man, his hands bound behind his back, is pushed to the ground. Then a man in military uniform delivers a forceful kick to the back of the prisoner's head with the heel of his boot. As the prisoner slumps forward, another soldier points his automatic weapon and fires a single shot. The man's body jolts. "It's like he jumped," laughs one of the giggling soldiers.
As gunfire rattles, the camera pans left to reveal a further seven bloodstained bodies, all handcuffed and bound, and – with one exception – similarly naked, strewn on the ground. The camera then pans right again, as another naked man is forced to the ground and shot in the back of the head. This time the body falls backwards.
These scenes, captured on video, allegedly show extra-judicial killings of Tamils by Sri Lankan troops earlier this year in the bitter and bloody endgame of the country's civil war. As government forces made a decisive thrust into the stronghold of rebel forces to end the decades-long conflict, a Sri Lankan soldier apparently took this footage, which was then smuggled out of the country by activists. It may constitute the first hard evidence for those who believe war crimes were committed in the effort to crush the Liberation Tigers of Tamil Eelam (LTTE). The significance of this footage – particularly shocking for the seemingly casual way in which the killings were carried out – is even greater given the way that journalists and independent observers were prevented by the government from reaching the war zone. The UN has estimated that 10,000 civilians were killed in what was, in effect, a war with no outside witnesses.
Last night the Sri Lankan army dismissed the footage as the latest in a series of fabrications designed to damage the country's image. But campaigners and Tamil politicians said it was vital that a full inquiry be carried out into the alleged killings. UN Secretary General Ban Ki-moon has voiced his support for an investigation into possible war crimes if convincing evidence emerged.
So too has Amnesty International's Asia-Pacific director, Sam Zarifi, who said: "We have received consistent reports that violations of the laws of war, as well as international human rights law, were committed by both sides in the conflict and we call once again for an international, independent and credible investigation into what took place during the final days of the conflict."
The footage was obtained by Journalists for Democracy in Sri Lanka (JDS), an organisation made up of several dozen Sri Lankan journalists who have fled into exile in recent years as the intimidation and killing of media professionals has soared. The group, whose members now live mostly in Europe, said the film was taken by a Sri Lankan soldier in January using his mobile phone as the army was battling to take the LTTE's de facto capital, Kilinochchi.
A spokesman for the group, who asked not be identified, said: "It was as if someone was filming it for fun. This was being circulated by the soldiers. It has been going round for a while. It was taken as if it was a souvenir." He said rumours of such footage had existed for a long time but that this was the first time such film had entered "the mainstream".
There is no way to confirm the authenticity of the footage, first broadcast by Channel 4 News. Likewise, there is no way of proving that the people apparently shot dead are Tamils, as the JDS has claimed. But this is not the first time that images from the war zone, captured on mobile phones, have been circulated within Sri Lanka.
Earlier this year a man in the eastern city of Trincomalee showed The Independent pictures of a naked, dead woman. He said the woman was apparently an LTTE fighter, killed as government troops advanced on rebel positions to the north.
Nor is it the first time that the army has been accused of carrying out summary justice. In May, when the rebels' final position in the north-east was overrun by government soldiers and the LTTE's leader, Velupillai Prabhakaran, was killed, it emerged that two other leading rebels had been shot dead while trying to surrender. Tamils living outside Sri Lanka said the two men were carrying a white flag when they were shot by troops. A senior government official admitted that the two men had been trying to give themselves up for several days. At the time, the EU called for an inquiry into possible human rights abuses committed during the final months of the war.
A spokesman for the UN High Commissioner of Human Rights (UNHCR) said: "If it can be verified, this footage could be evidence of the sort of war crimes we fear were committed by both sides. We have repeatedly said there should be an investigations into the closing stages of the conflict. There needs to be some sort of accountability."
The final assault on the LTTE ended a war that had raged for almost three decades and cost at least 70,000 lives. The LTTE, fighting for a Tamil homeland, had long waged a brutal insurgency and used suicide bombers to attack both civilian and military targets. Since the war ended, the popularity of President Mahinda Rajapaksa, whose brother heads the powerful defence ministry, has soared among the country's Sinhala majority.
The resulting peace has also seen a 25 per cent increase in the number of visitors to Sri Lanka, lured by its beaches, tropical forests and gently paced culture. Already about 100,000 visitors from the UK travel to the island each year, according to the Sri Lankan tourist board, and officials are hopeful that the tourist numbers will increase further.
When he announced an end to the war, the president said that Sinhala, Tamils and Muslims must live as "equals". Yet some Tamils say the government has done little to placate its population or to offer them a political "settlement". This summer, in local elections held in the north, the government's party won in the city of Jaffna, but in Vavuniya victory went to the Tamil National Alliance (TNA), which has previously voiced some support for the LTTE.
Yesterday Sri Lankan opposition MPs urged the government to release nearly 300,000 war refugees held in state-run camps, saying the detentions brought discredit to the country.
"These camps stand as a symbol of shame and disgrace to our proud Sri Lankan history," said Mano Ganesan, an opposition MP and leader of a group calling itself Parliamentarians for Human Rights. "They are like prisons. People are kept against their will and that's illegal."