The UN Human Rights Council Thursday passed a resolution urging Sri Lanka to conduct a credible investigation into alleged war crimes during its battle against Tamil Tiger separatists in 2009. Sri Lanka bristled as its ally India turned its back on Colombo during the council\'s contested vote on the US-led resolution, while rights groups said the result sent a \"strong message for justice.\" Tabling the resolution, the United States said Colombo had been given three years to hold its own investigations into allegations of serious violations, but \"given the lack of action... it is appropriate\" that the 47-member-state council pushed it to do so. In Washington, Secretary of State Hillary Clinton hailed the council\'s action, saying it \"encourages the government of Sri Lanka to continue on the path toward reconciliation following 27 years of civil war.\" \"The United States, together with the international community, sent a strong signal that Sri Lanka will only achieve lasting peace through real reconciliation and accountability, and the international community stands ready to help,\" she said. Rights groups say up to 40,000 civilians died in the final months of Colombo\'s military campaign to crush the Tamil Tigers, who waged a bloody decades-long campaign for a separate homeland for minority Tamils. The government has denied its troops were responsible for any non-combatant deaths, but UN mandated experts have accused the Sri Lankan army of killing most of the civilian victims in their final offensive against the separatists in 2009. The United Nations estimates some 100,000 people died during Sri Lanka\'s ethnic conflict between 1972 and 2009. US envoy Eileen Donahoe noted in particular that India\'s backing was \"very helpful because they are such a close neighbour\". \"We see India\'s support as nothing but positive,\" she said. But Sri Lanka called the move \"distressing\" with its Foreign Minister G. L. Peiris charging that \"voting at the Human Rights Council is now determined not by the merits of a particular issue but by strategic alliances and domestic political issues in other countries.\" Sri Lanka\'s human rights envoy Mahinda Samarasinghe also dismissed the \"misconceived, unwarranted and ill-timed resolution which embodies several harmful elements that clearly violate important principles that will have adverse ramifications, not only for my country, but many other countries.\"  He insisted that Sri Lanka must be given time to allow its domestic investigations to run their course and warned that the resolution would be counter-productive. It would \"also undermine the principle of non-interference in matters within the domestic jurisdiction of a country,\" he added, a point backed by China and Russia. India did not take the floor during the debate, but the foreign ministry issued a statement after the vote, saying that Colombo \"has to be provided time and space to achieve the objectives of reconciliation and peace.\" India added that \"it would continue to remain engaged with the government of Sri Lanka to take forward the process of reconciliation.\" International rights activists welcomed Thursday\'s decision as a step in the right direction. \"Many countries have recognised that this resolution is an important first step toward serious action to investigate the many abuses by both sides during the conflict,\" said Juliette De Rivero, advocacy director at Human Rights Watch. Amnesty International\'s Sam Zarifi said it was an \"opportunity to end the longstanding impunity for human rights violations that have marked the country for decades.\"