Security has been stepped up in Lucknow, particularly at the Hindustan Aeronautics Limited premises, after an SMS threatening a blast was received by the office of the Director General of Police.

Police officials confirmed that an SMS was received on Wednesday and security measures were tightened immediately at important places of the state capital.

''We are tracing out the numbers from where the SMS came from and further action would be taken against the offender,'' the police officer said.

The Anti-Terrorist Squad of the state police has been entrusted with the investigation into the case. As the SMS was received after the Jaipur serial blasts, the state police was not taking any chances. It has stepped up the security measures in Lucknow.

Meanwhile, Lucknow Senior Superintendent of Police  Akhil Kumar said that on the directives of the senior officials, a 10 commando team of the Quick Reaction Team, equipped with AK-47, had been deployed at HAL since Wednesday evening.