Karunanidhi on Tuesday announced that five ministers of the party would submit their resignations shortly following the controversy on India's stand on resolution against Sri Lanka.
"The plight of Sri Lankan Tamils is very close to our hearts," she told Congress MPs at a meeting in parliament house in New Delhi on Tuesday.
"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 told the law-makers.
"Our support for their (Tamil) equal rights and equal protection ... has been unwavering since the days of Indiraji and Rajivji. We are most pained at the manner in which their legitimate political rights continue to be denied to them," said Sonia Gandhi.
On the harassment of Indian fishermen and those who were detained or fired at by the Sri Lankan Navy, she said it was a matter of grave concern. "A permanent solution to the daily violence against them (fishermen) is also imperative," she said.