A year after defeating Tamil Tiger rebels, accusations of war crimes are still haunting against the Sri Lankan government.

The government is under continuous pressure from human rights groups to initiate an international investigation soon after the UN claimed that over 7,000 civilians were killed in the final days of the battle that ended in May 2009.

More than 70,000 people were killed in the 30-year-old civil war between the government troops and the Liberation Tigers of Tamil Eelam (LTTE), which had been fighting for an independent Tamil homeland in the north and east before it was defeated.

Soon after ending the battle, Canadian Tamil Diaspora urged the European Union (EU) and the UN Human Rights Commission (UNHRC) to set up an international tribunal to investigate war crimes in the conflict.

Three human rights groups -- the International Crisis Group ( ICG), Human Rights Watch (HRW) and Amnesty International -- renewed their calls to probe alleged human rights violations as Sri Lankan government celebrated its first war victory anniversary this year.

UN Secretary-General Ban Ki-moon set up a advisory panel last month to look into alleged human rights abuses during the final stages of Sri Lanka's civil war in 2009. Ban's spokesman said the three-man panel would advise him on how to deal with alleged perpetrators.

The EU on Thursday welcomed the appointment of the panel, saying the EU encourages Sri Lanka to cooperate fully, including through the Lessons Learnt and Reconciliation Commission appointed by President Mahinda Rajapaksa, with the members of the panel, in the interest of all concerned.

The appointment came after the call of UN High Commissioner for Human Rights Navi Pillay to expose the alleged violations occurred during the last lap of the civil war.

"Based on previous experience and new information, I remain convinced that such objectives would be better served by establishing an independent international accountability mechanism that would enjoy public confidence, both in Sri Lanka and elsewhere," Pillay said.

Meanwhile, Pillay has accredited the government for appointing post-war reconciliation commission which looks into alleged violations of human rights.