Sri Lankan security forces committed the "vast majority" of war crimes, including arbitrary killings, torture and rape, in the final months of the country's civil war, a new investigation claimed today. 

The report, released by the Australia-based Public Interest Advocacy Centre (PIAC), had accused government troops of trying to destroy evidence of its crimes committed in 2008 and 2009 when it crushed the Tamil rebels fighting for a separate homeland. 

"Although violations were committed by both sides, the evidentiary material indicates that members of the Sri Lankan security forces perpetrated the vast majority of alleged crimes during the investigation period," the report said. 

The investigation, that came ahead of a third resolution at the UN Human Rights Council (UNHRC) next month, also claimed that the Sri Lankan government "may have sought systematically to exhume and destroy evidence of mass civilian deaths".

The US has said it would table the third resolution against Sri Lanka over alleged war crimes committed by government troops  during the final phase of the military battle with the LTTE.

Sri Lanka encountered similar UN resolutions both in 2012 and 2013, moved by the US and supported by India.