US notches up security in the wake of the botched car bomb plot

US officials yesterday ratcheted up security in the wake of the botched Times Square bomb plot amid a growing global investigation into a Pakistani-American suspect's links to terror groups.

Washington tightened "no-fly" procedures after the alleged New York car bomber was allowed to board a flight to Dubai despite being red-flagged by the authorities.

Suspect Faisal Shahzad, 30, who has been charged with five counts of terrorism, almost fled aboard an Emirates flight from New York as he realised US police were closing in on him, US officials have revealed.

With the investigation now focusing on a motive, officials say Mr Shahzad has been cooperating during questioning since he was arrested late on Monday after his plane was stopped as it taxied down the runway at John F. Kennedy airport.

In the latest of a string of foiled attacks targeting the US, Mr Shahzad allegedly drove a Nissan SUV Pathfinder crammed with a large, but malfunctioning, bomb into Manhattan's busiest theatre district late on Saturday.

The attack was stopped when a street vendor spotted smoke coming from the car. Amid the massive manhunt, officials have denied Mr Shahzad almost managed to escape.

"I was never in any fear that we were in danger of losing him," Attorney General Eric Holder told a press conference on Tuesday.

But US aviation officials said yesterday they had stepped up security requirements demanding airlines check "no fly" lists within two hours of learning of a "special" name, instead of the previous requirement of 24 hours.

"In his case, the airline seemingly didn't check the name, and the suspect was allowed to purchase a ticket and obtain a boarding pass," a Transportation Security Administration official said.

Investigators are meanwhile probing whether Mr Shahzad, who says he acted alone, had any links to extremist groups, after the attempted bombing was claimed by the Pakistan Taliban.

In an unexplained delay, Mr Shahzad has yet to appear in court, although Holder said he had admitted to planning the attack during his ongoing interrogation.

According to the US criminal complaint, Mr Shahzad, who became a US citizen last year, admitted "after his arrest that he had received bomb-making training in Waziristan, Pakistan."

The alleged visit to the Al-Qaeda and Taliban stronghold presumably occurred during a five-month trip the complaint says Mr Shahzad, the son of a retired air force officer, made to Pakistan earlier this year without his wife.

But Pakistan's military said it had yet to establish a link between Mr Shahzad and the country's main militant stronghold in Waziristan.

"Until and unless the link is established, it will be premature to say that he had gone there," army spokesman Athar Abbas said.

Waziristan is the powerbase of Tehreek-e-Taliban Pakistan (TTP), which has been the only militant group to claim Saturday's attempted bomb attack, albeit in a move widely disputed in Pakistan and the US.

Pakistan's Foreign Minister Shah Mehmood Qureshi warned, however, yesterday that the foiled attack could be retaliation for US drone attacks on the Taliban, which have triggered anger in his country.

"This is retaliation. And you could expect that... let's not be naive," Qureshi told CBS television. They're not going to sort of sit and welcome you (to) sort of eliminate them. They're going to fight back."

The US has significantly increased drone strikes on North Waziristan this year, with more than 890 people have been killed in nearly 100 drone strikes in Pakistan since August 2008.