Here are 10 big developments in this story:
Mr Karunanidhi today said, "India's appreciation of Sri Lanka led to the deletion of a demand for international investigation."
The US-backed resolution only calls for an "independent and credible investigation" by Sri Lanka into violations of humanitarian law.
The government has rejected the DMK chief's charge. "It is a canard that India diluted the resolution sponsored by the US," said Finance Minister P Chidambaram today.
Three of the DMK's five ministers gave in their resignations to the Prime Minister this morning. Mr Karunanidhi's son and Cabinet minister MK Alagiri met the PM separately, the latest expression of his rivalry with his brother, MK Stalin, who allegedly scripted the DMK's pullout from the UPA.
At a press conference this morning, Finance Minister P Chidambaram announced that India has decided to move amendments to the UN resolution and that other political parties were being consulted over it.
Political opinion is deeply divided over whether India should move a parliamentary resolution against Sri Lanka, a key DMK demand. The BJP has made it clear it will oppose any such move, saying it will compromise India's foreign policy.
The government insists that even with the exit of the DMK, it will be able to muster enough support to pass pending reform legislation, especially in the pension and insurance sectors. (Read)
A vote on the UN resolution, which addresses the alleged atrocities against the country's Tamil civilians during Sri Lanka's decades-long war, will be held tomorrow in Geneva where the UN Human Rights Council is in session.
Sources say that for its amendments to be accepted, India would need the support of 24 out of 47 member countries, which is unlikely.
The UN has estimated that some 40,000 people were killed in the final months of the Sri Lankan civil war, while rights groups put the death toll even higher. Sri Lanka denies that its forces killed civilians.
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