FBI warns of possible al Qaeda New York subway plot, police on alert .hurriyet2008-detailbox-newslink { font-family: Arial, Helvetica, sans-serif; font-size:13px; font-weight:bold; text-decoration:none; color:#000000;} .hurriyet2008-detailbox-newslink:hover { font-family: Arial, Helvetica, sans-serif; font-size:13px; font-weight:bold; text-decoration:underline; color:#990000;} The FBI has warned U.S. officials of a possible al Qaeda plot against New York's subway and transport grid, putting the city's police on heightened alert Wednesday.

Extra police were stationed around major hubs in the city even though the FBI said the threat, which came on the eve of the national Thanksgiving holiday, was unsubstantiated.

The FBI received "uncorroborated but plausible information that al Qaeda may have discussed a target at the transit system in New York City," Amy Kudwa, a spokeswoman for the Department of Homeland Security told AFP.

"Neither the Department Homeland Security nor the FBI has any specific information to confirm that this plot has developed beyond aspirational planning," she said.

The New York Police Department's deputy commissioner, Paul Browne, said authorities were "aware of an unsubstantiated report indicating that al Qaeda terrorists discussed targeting mass transit in New York City and vicinity."

He added that although there was no evidence to suggest the discussions had advanced any further, as a precaution "the NYPD has deployed additional resources in the mass transit system."

ABC television quoted unnamed law-enforcement sources as saying that the attack under discussion targeted Penn Station, a major subway and rail hub in Manhattan.

Extra police could be seen at Penn Station, with six squad cars parked together outside, as well as a command truck at a separate location.

Inside the stations hall for north-eastern Amtrak trains, five armed officers patrolled in helmets and flack-jackets, and with sniffer dogs.

"I see a lot of law enforcement, more than usual," said Wall Street worker Vishal Rawal, 25, who commutes daily between Manhattan and New Jersey.

"Of course I am concerned. Even if I am too busy with work, it is always on your back," he added.

At the nearby Port Authority bus terminal and at Grand Central rail and subway station, the police presence was not visibly higher than usual.

The U.S. terror alert level has not been raised, officials said.

However, the al Qaeda scare came ahead of Thursday’s Thanksgiving holiday, when millions of Americans travel to see friends and family.

According to the ABC report, the plot involved a "Madrid-like attack" on Penn Station, a reference to the bombing of Spanish trains in March 2004 that killed 191 people.

Spanish courts last year ordered 21 people jailed for life in connection to the synchronized wave of bombings against Madrid commuter trains on March 11, 2004. Four have since been acquitted after appeals.

New York has remained on an orange alert -- the second highest level, below red -- since the September 11, 2001, attacks that destroyed the World Trade Center. The rest of the United States is on yellow alert, one level below orange.
In October 2005, New York City's subway system was on high alert after detainees in Iraq were thought to be plotting a bomb attack, but the threat was later found to lack credibility.
In August 2007 police stepped up security throughout Manhattan and at bridges and tunnels in response to an unverified Internet report that al Qaeda might be plotting to detonate a dirty bomb in the city.