Police and revenue officials should take joint efforts to differentiate between genuine refugees and anti-social elements, he said, inaugurating District Collectors' conference at Secretariat here.
Due to the tense situation prevailing in the island nation, Tamil refugees had been arriving in the state since January 12, 2006. So far 13,844 refugees had reached Tamil Nadu, seeking safety and livelihood, he added.
''Though it is our duty to lend a helping hand to the refugees, we should not allow anti-social elements on our soil in the garb of refugees,'' he said.
Expressing satisfaction over the law and order situation, he urged Collectors and police officials to ensure that terrorism did not raise its ugly head in the state.
The authorities should identify problematic areas and be vigilant to prevent any untoward incident, he said.
Mr Karunanidhi's remarks assumed significance in the wake of some suspected LTTE militants escaping from a quarantine centre in Rameswaram recently.
UNI AKN JJ PDM BS1729