India promised Wednesday to push for a "strong" resolution against Sri Lanka in the ongoing United Nations Human Rights Council that would demand its neighbour investigate alleged war crimes.
The issue split India's ruling coalition and heightened the risk of early elections on Tuesday, when a regional ally quit the government after demanding that India condemn "genocide" against minority Tamils in Sri Lanka's civil war.
India will propose unspecified amendments to a draft resolution being drawn up by the United States, Finance Minister P. Chidambaram said before an expected vote on the text at the Geneva-based UNHRC on Thursday.
"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.
Sri Lanka has denied that its forces committed war crimes during the decades-long conflict with Tamil separatists in the north and east of the island, which ended with an military onslaught in early 2009.
International rights groups estimate that 40,000 civilians died in the final months of fighting.
India, home to millions of Tamils who share links with their counterparts in Sri Lanka, risks a further worsening in relations with Sri Lankan President Mahinda Rajapakse who has resisted any foreign interference.
Sri Lanka on Wednesday warned pilgrims against travelling to the south Indian state of Tamil Nadu, a day after lodging a formal protest with New Delhi over repeated physical attacks against visiting Sri Lankans.
Dozens of Buddhists monks demonstrated outside the Indian embassy in Colombo for a second straight day on Wednesday. India has postponed scheduled defence cooperation talks this month, officials said.
In another move likely to deepen the discord, Chidambaram said the government was consulting other parties about a parliamentary resolution which would also call on Sri Lanka to investigate the alleged war crimes.
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".
Sri Lanka's top general, who led the campaign against the Tamil Tiger rebels, said Tuesday the government should accept an investigation 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 is now a top opposition figure, 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."
The Dravida Munnetra Kazhagam, a regional Indian party from the state of Tamil Nadu, said on Tuesday it would quit the New Delhi government for failing to condemn Sri Lanka in sufficiently strong language.
The move leaves the government more vulnerable to falling before the scheduled date for elections in the first half of 2014.