Sri Lanka has accused the United Nations rights chief of 'unwarranted interference' in the country.
Navi Pillay had called for an international probe into allegations that the Sri Lankan government forces killed thousands of civilians at the climax of a Tamil civil war.
According to Dawn News, President Mahinda Rajapakse's government formally rejected Pillay's demand for an external investigation into 'credible allegations' that 40,000 ethnic Tamil civilians were killed by Sri Lankan forces in 2009.
Colombo said that Pillay's recommendation to a UN Human Rights Council (UNHRC) meeting in Geneva next month 'reflects bias and is tantamount to an unwarranted interference in the internal affairs of a sovereign state', the report said.
According to the report, Sri Lanka's latest criticism of the UN official, set out in a 23-page statement, accused her of having a 'preconceived, politicised and prejudicial agenda, which she has relentlessly pursued with regard to Sri Lanka'.
In a UN document leaked 10 days ago, but published officially on Monday, Pillay asked the UNHRC to set up an independent probe, adding that Colombo had 'consistently failed to establish the truth,' the report added.