The 47-member United Nations Human Rights Council (UNHRC) at its ongoing 30th session here approved by consensus a crucial resolution led by the US and the UK, and backed by Sri Lanka itself, in a move hailed by international advocacy groups.
According to a UNHRC spokesperson, there was no voting and there were no last-minute revisions in the text of the draft resolution titled "Promoting reconciliation, accountability and human rights in Sri Lanka".
Rights groups claim that the military killed 40,000 civilians in the final months.
The proposed mechanism will include Special Counsel's office, of Commonwealth and other foreign judges, defence lawyers, and authorised prosecutors and investigators.
Besides asking Sri Lanka to form a credible judicial system for the probe, the resolution - based on a landmark report issued by the UN last month - also calls on Sri Lanka to allow for punishment of "those most responsible for the full range of crimes".
