Chennai, June 13: Chief minister M. Karunanidhi?s son and heir apparent M.K. Stalin today escaped an assassin?s knife, thanks to an alert constable who spotted the attacker minutes after the DMK leader stepped off a train in Madurai.

Police sources in the temple city said the Tamil Nadu minister had just got off the Pandiyan Express from Chennai to a rousing welcome and was walking towards his car when the ?unknown? assailant crept up from behind.

But the constable, one of the eight CRPF personnel assigned by the Congress-led central government to guard the youth leader, overpowered the man who dropped the knife and melted into the 700-strong crowd in the railway station. The constable suffered cuts on two fingers and was later treated at a local hospital.

The sources said Madurai Railway Police have registered a case of attempt to murder but, till this evening, the assailant, believed to be in his thirties, was still at large.

This is Stalin?s first official visit to Madurai since the DMK?s return to power last month.

The local administration and rural development minister is on a two-day tour of the districts and is also scheduled to address a public meeting in Nagercoil tomorrow.

Stalin did not realise he had been attacked and came to know of the attempt only after he reached his car. ?When I alighted from the train here, I felt somebody pulling my shirt from the back. I thought someone, in his eagerness to come close to me had done so. But later I understood that he was wielding a knife.?

Asked why he had been targeted, he said: ?I do not know the motive.?

Stalin?s brush with what could have been a fatal attack has come at a place notorious for intra-party rivalries in the DMK. A few years ago, veteran leader and former minister Pasumponn T. Kiruttinan was hacked to death while on a morning stroll.

However, the rival factions had closed ranks during the recent Assembly polls, which saw the DMK-Congress alliance canter home with ease.

The Congress, which supports the Karunanidhi government from outside, condemned the attempt.

In state capital Chennai, legislature party leader D. Sudarshanam and another senior leader, Peter Alphonse, demanded strong action against the culprit who, they said, symbolised a ?new culture of political violence? being ?fostered by some anti-social elements? after the DMK?s victory.

Alphonse ruled out intra-party rivalry behind the attack. ?Why should there by rivalry now when there was no such thing even during the Assembly elections?? he asked. ?We suspect anti-socials, who do not want the new DMK government to settle down, to be behind this attack.?