The security arrangements for Tamil Nadu Chief Minister M Karunanidhi were strengthened on Saturday after officials received a hand-written letter threatening to kill him with a human bomb.
According to the police, officials received the letter purportedly written by the banned Al Umma organisation, saying a human bomb would blow up Karunanidhi. The chief minister is visiting this hosiery town to announce upgradation of its municipal committee to a municipal corporation.
The letter also demanded that the upper age limit for youth to join the police force should be raised to 29 years from the present 24 years.
"Despite this measure being promised by the government, it has not been implemented," the letter reportedly said.
Tirupur is in the grip of mass unemployment as the southbound US dollar has rendered the hosiery industry unviable.
Nearly 2,000 police personnel are deployed as part of Karunanidhis' security detail. He is scheduled to visit the neighbouring town of Erode later on Saturday.
Top Al Umma leaders, including Syed Ahmed Basha and Mohammed Ansari, were awarded multiple life sentences in Coimbatore by a special court for the Feb 14, 1998, bomb blasts targeting Bharatiya Janata Party Leader LK Advani.