NYPD chase bomb threat to 9/11 ceremony

US counter-terrorism officials are pursuing a credible but unconfirmed al-Qaida threat to set off a car bomb on bridges or tunnels in New York or Washington.

It was the first word of an “active plot” timed to coincide with the sombre commemoration of the group’s 9/11 attacks a decade ago tomorrow that killed nearly 3,000 people.

The threat was being investigated as police in both cities said they had increased their already stepped-up staffing levels in light of the recent intelligence.

Law enforcement officials were pursuing three people who may be travelling to the US or who have recently entered the country, based on information received by the US intelligence community, officials said. The intelligence suggested al-Qaida planned to car-bomb one of the two cities that were hit 10 years ago.

Vice-president Joe Biden said that there was no confirmation that anyone had travelled into the US for such a plot, but the tip came from a credible source. “There’s no certitude,” he said.

“The thing we are all most worried about is what they call a ‘lone ranger’, a lone actor, not some extremely complicated plan like it took to take down the World Trade towers,” said Biden.

A US official said the tip indicated that al-Qaida’s new leader, Ayman al-Zawahri, was involved in the plot. But they also said that many officials question aspects of the source’s information.

The US terror alert level has not changed, but raising it was under consideration.

The FBI and Homeland Security Department issued a joint intelligence bulletin to law enforcement around the country, urging them to maintain increased security.

The threat was so specific that it could not be ignored, officials said.

“There is specific, credible, but unconfirmed threat information,” said the head of the FBI’s New York division, Janice Fedarcyk.

New York Mayor Michael Bloomberg stated that police there were deploying additional resources, around the city, but New Yorkers should go about their business as usual, and the city’s observance of the attacks will go on.

President Barack Obama is to mark the day with stops at Ground Zero, the Pentagon, Shanksville, Pennsylvania, and at a memorial concert at the Kennedy Centre in Washington.