New Delhi (PTI): India on Monday expressed "grave concern and unhappiness" at the growing casualties of unarmed Tamil civilians in the military offensive in Sri Lanka and asked the government in the island nation to "act with greater restraint".

As the issue of the killings hotted in up in Tamil Nadu, National Security Adviser M K Narayanan summoned Sri Lankan Deputy High Commissioner G G A D Palithaganegoda to convey India's concerns to him.

"......was summoned to express India's concern and unhappiness at the growing casualties of unarmed Tamil civilians as a result of military action. The escalation of hostilities in the North and the resultant fall out was leading to a great deal of concern in India," a statement by the External Affairs Ministry said here.

The NSA's move came after Prime Minister Manmohan Singh assured the Tamil Nadu Chief Minister M Karunanidhi that his government would take all steps to stop the 'genocide' of Tamils in Sri Lanka. He had telephoned Karunanidhi to discuss the Sri Lankan issue, a Tamil Nadu government press release said in Chennai.

During the telephonic conversation, Karunanidhi referred to the 'genocide' of Tamils in Sri Lanka and requested the Prime Minister to summon the Sri Lankan High Commissioner in Delhi to convey India's strong protest on the "killings."

The External Affairs Ministry statement said it was pointed out to the envoy that there was need for the Sri Lankan government to act with greater restgraint and address the growing feeling of insecurity among the minority community.