India’s main airports were on a state of high alert last night amid fears that 14 terrorists given the same training as the Mumbai gunmen are preparing to mount a 9/11-type attack using hijacked passenger aircraft.

The Defence Minister, A. K. Antony, ordered the nation’s armed forces to be on guard against “terror strikes from the air” eight days after India suffered its worst terrorist attack in 15 years, when at least ten gunmen struck targets including a hospital, two luxury hotels and a backpacker bar in south Mumbai, killing 171 people.

The India Bureau for Civil Aviation is thought to have been warned of plans to capture one or more aircraft at Delhi, Mumbai, Bangalore or Madras airports, the main Indian transport hubs. Officials said that credible intelligence indicated a plan to attack a significant population centre using an airliner in an assault that would resemble those made on New York and Washington in 2001.

The warning recalled the Indian Airlines flight that was hijacked by Pakistani nationals on Christmas Eve 1999 as it flew from Kathmandu to Delhi. It landed in Afghanistan, where the hostages were released in exchange for three Islamist extremists.

Last night armed police were manning cordons at each airport and passengers were told to arrive three hours before their flights to go through bolstered security procedures. The Air Force said that fighter aircraft were being deployed and that plans to move anti-aircraft missiles to “high-value areas” were being studied.

The Indian air infrastructure has failed to keep pace with the country’s booming aviation industry, in which passenger numbers rose by 30 per cent last year. Experts fear that usual security arrangements could be breached easily by trained militants.

Azam Amir Kasab, the sole Mumbai gunman to be caught alive, has told interrogators that he was one of 24 men being trained in militant camps in Pakistan. So far, only ten — Kasab and nine others who were killed in Mumbai — have been accounted for.

“The whereabouts of the 14 missing men is of utmost concern,” a police source said. Interrogators hoped to extract more information from Kasab by subjecting him to narcoanalysis.

The faith of Mumbai’s residents in their security forces, already sorely tested, was dealt another severe blow this week when a bag containing 8kg (18lb) of explosives was found in Chhatrapati Shivaji Terminus (CST), the main Mumbai railway station.

Kasab and an accomplice killed 56 people at CST on Wednesday last week. It is thought that the explosives, which were found with the bags of passengers who fled the station that night, had lain there undiscovered since the attacks.

Yesterday it emerged that a private company that supplies explosives sniffer dogs to one of the rail operators in Mumbai had withdrawn its services because a bill of about £2,000 had not been paid. A Western Railway official refused to comment. There was also a report that a sighting of the terrorists off the coast of Gujarat as they made their way by sea to Mumbai by Indian security forces was not acted on.

A message sent to an Indian news agency threatened an attack tomorrow. It alleged to be from the Deccan Mujahidin, a previously unknown group that claimed to be behind the attacks on Mumbai, but which most experts suspect is a front for more established terrorist factions.

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