New Delhi: Congress president Sonia Gandhi on Tuesday denounced Sri Lanka for the "unspeakable atrocities" on Tamils, taking an unusual hard line against Colombo for the first time.
Gandhi's comments made to Congress MPs in the parliament complex came hours before the DMK announced it was quitting the ruling UPA to protest New Delhi's stand on Sri Lanka at the UNHRC session in Geneva.
And echoing demands being made across the political spectrum in Tamil Nadu, Gandhi sought an independent and credible probe into rights abuses in Sri Lanka.
"The plight of Sri Lankan Tamils is very close to our hearts," a Congress source quoted Gandhi as saying.
"We are anguished by the reports of unspeakable atrocities on innocent civilians and children, especially during the last days of the conflict in 2009.
"That is why we demand an independent and credible inquiry into the violation of human rights in Sri Lanka," she added.
"Our support for their (Tamil) equal rights and equal protection has been unwavering since the days of Indiraji and Rajivji," she said, referring to former prime ministers Indira Gandhi and Rajiv Gandhi, her late mother-in-law and husband.
"We are most pained at the manner in which their legitimate political rights continue to be denied to them," said Gandhi.
It was the first time in recent years that any top Indian leader has publicly spoken out against Sri Lanka using such strong language.
Gandhi was widowed when her husband Rajiv Gandhi was assassinated by a Tamil Tiger suicide bomber at an election rally near Chennai in May 1991.
Sonia Gandhi's comments came ahead of mounting pressure on the Indian government to take a hard line vis-a-vis Sri Lanka at the UN Human Rights Council session in Geneva.
The DMK on Tuesday quit the Congress-led United Progressive Alliance saying the government must denounce the "genocide" of Tamils in Sri Lanka.
The DMK also wants an independent international investigation into the reports of deaths of thousands of Tamils in the end stages of the conflict that vanquished the Tamil Tigers in 2009.
Talking about Indian fishermen detained or fired at by the Sri Lankan Navy, Gandhi said it was a matter of grave concern.
"A permanent solution to the daily violence against them is also imperative," she said.
The assaults on fishermen from Tamil Nadu in the high seas allegedly by the Sri Lanka Navy has also ignited passions in the southern Indian state.