India promised Wednesday to push for a "strong" UN resolution urging Sri Lanka to investigate alleged war crimes, a day after the issue caused a split in the ruling coalition.
The United States is drafting a resolution against Sri Lanka at the United Nations Human Rights Council in Geneva which is expected to be voted on Thursday and is bound to anger Colombo.
Finance Minister P. Chidambaram said India would propose amendments to the draft resolution being negotiated, but he denied that India was trying to water it down -- as was claimed in some media reports.
"India's position has always been and remains that the UNHRC should adopt a strong resolution that would send a resolute message to Sri Lanka and goad Sri Lanka to accept an independent and credible investigation," Chidambaram said.
India's ruling coalition was rocked on Tuesday by the resignation of a party from southern Tamil Nadu state, which accused the government of being too soft and demanded that the resolution refer to the "genocide" of ethnic Tamils.
International rights groups estimate that 40,000 civilians died in the final months of fighting when government troops launched an onslaught on separatists fighting for a Tamil homeland.
Sri Lanka has denied that its forces killed civilians and has resisted calls from the UN and Western powers for an independent international investigation into the conduct of its army.
Sri Lanka's top general, who led the campaign against the Tamil Tiger rebels, said Tuesday the government should accept a probe but he rejected any suggestion of genocide.
"Some people have questions. Some people have doubts. Some people want to know what happened," Sarath Fonseka, who has become a top opponent of President Mahinda Rajapakse, told the Foreign Correspondents' Association.
"We will have to justify the actions taken by us. I am ready to answer anyone. I am ready to clarify any doubts."
India, home to millions of Tamils who share links with their counterparts in Sri Lanka, risks a further worsening in relations with its southern neighbour over the UNHRC resolution.
Leader of the ruling Congress party, Sonia Gandhi, said Tuesday that India was "most pained" that Tamils in Sri Lanka were being denied their rights and New Delhi was "anguished by reports of unspeakable atrocities".
Thousands of Tamils held protests in Tamil Nadu on Wednesday as well as in the commercial capital Mumbai, holding up pictures of alleged victims of Sri Lankan soldiers.
India has also postponed scheduled defence cooperation talks with Sri Lanka this month, officials told AFP.
In Sri Lanka, dozens of Buddhist monks demonstrated outside the Indian embassy in Colombo for a second straight day on Wednesday.
The country has lodged a complaint with India and warned its pilgrims against travelling to Tamil Nadu because of repeated physical attacks against them.
In another move likely to deepen the discord, Chidambaram stressed that the Indian government was consulting other parties about a parliamentary resolution which would also call on Sri Lanka to investigate the alleged war crimes.
The Dravida Munnetra Kazhagam, which quit the coalition on Tuesday, has hinted that it might return to support the government if a resolution is passed by parliament.
Without its 18 lawmakers in the lower house, the left-leaning government, dominated by the Congress party, is more vulnerable to falling before the scheduled date for elections in the first half of 2014.