UPDATE 1-U.N. ready to support Sri Lanka war inquiry-Pillay

* Navi Pillay says accountability needed for Sri Lanka peace * Cites concerns about Pakistan, Afghanistan, Iraq, Colombia

(Adds Sri Lankan response)

By Laura MacInnis

GENEVA, June 4 (Reuters) - The United Nations stands ready to support an inquiry into abuses in Sri Lanka's civil war, U.N. High Commissioner for Human Rights Navi Pillay said on Thursday.

Addressing the U.N. Human Rights Council, which last week avoided launching an investigation into the Sri Lankan conflict, the former war crimes judge stressed that reconciliation would be impossible without a full reckoning of transgressions.

"I believe that accountability is a prerequisite for the attainment of justice and reconciliation for all Sri Lankans and, thus, a foundation for lasting peace," she said.

Pillay, who is an ethnic Tamil from South Africa, said the Liberation Tigers of Tamil Eelam (LTTE) and the military both ought to held responsible for killing and mistreating civilians in the last throes of their 25-year conflict.

Her remarks sought to keep up pressure on Sri Lanka in spite of the Human Rights Council's failed attempt to scrutinise the conduct of both sides during and after the 25-year separatist war that Colombo declared over last month.