|Mahinda Rajapaksa has opted for an internal investigation into alleged war crimes committed by Sri Lankan troops during the conflict with the Tamil Tiger rebels [EPA]
Another leaked US embassy cable released by whiste-blowing website WikiLeaks has added weight to calls for an independent inquiry into the final days of Sri Lanka's civil war.
US diplomats in Sri Lanka believe the country's president carries much of the responsbility for the mass deaths of ethnic Tamil civilians in the final days of the civil war.
According to the cable written by Patricia Butenis, the US ambassador, Mahinda Rajapaksa, his generals and family members are implicated.
The UN has said that at least 7,000 ethnic Tamil civilians were killed in the final months of fighting.
Butenis wrote in January that responsibility for many of the alleged crimes rests with the country's senior civilian and military leadership, including President [Rajapaksa] and his brothers and opposition candidate General Fonseka," she said, according to WikiLeaks.
Gotabaya Rajapakse, the president's brother, is defence secretary.
Former general Sarath Fonseka led the army's defeat of the Tamil Tigers but was arrested shortly after losing a presidential bid this year.
Rajapaksa has resisted external pressure for an international probe into allegations that both the rebel Tamil Tigers and the military committed war crimes during the conflict.
He has instead opted for an internal investigation, a move that was also questioned by Butenis.
According to the cable, Butenis, said that "there are no examples we know of a regime undertaking wholesale investigations of its own troops or senior officials for war crimes while that regime or government remained in power."
The document also shows Butenis questioning whether the Tamil Tiger fighters captured by government forces will receive a fair trial.
"The Government of Sri Lanka is holding thousands of mid- and lower-level ex-LTTE [Tamil Tiger] combatants for future rehabilitation and/or criminal prosecution. It is unclear whether any such prosecutions will meet international standards." she said.
Last year, the army killed the top Tamil Tiger leadership, during a nearly four-decade campaign in which they fought for a separate Tamil homeland.
The revelations coincide with Rajapaksa's visit to the United Kingdom. Noisy protests at London's Heathrow Airport greeted the Sri Lankan president when he arrived on Monday.
the Oxford Union, Britain's prestigious debating society,, has cancelled a speech he was due to give, citing security reasons, as Tamil activists were said to be planning a large demonstration outside the venue.