New York/Washington: Heavily-armed counter- terrorism forces were deployed in New York after US officials warned of a new "credible" threat of a strike on the city by al-Qaeda using car or truck bomb, coinciding with the 10th anniversary of the 9/11 attacks.

The extra police forces were deployed after officials briefed President Barack Obama of the situation and New York Mayor Michael Bloomberg disclosed that the terror threat to the city is "credible but not corroborated".

"The President directed the counter-terrorism community to redouble its efforts in response to this credible but unconfirmed information," a White House official said.

The threat was received by the US intelligence agency on Wednesday and the officials have put a look out notice for three people, who entered the country last month by air traveling from Afghanistan via a third country.

Counter-terrorism officials were assessing the report and media reports said that authorities were contemplating raising the threat level in New York and Washington.

The agencies are also pursuing the leads overseas in an effort to unravel the plot, a statement by a spokesman for the department of Homeland Security said.

Further, a nationwide hunt has been launched for at least two missing rental trucks that remain untraceable from locations in Kansas City, Missouri, officials said.

The scare came days ahead of anniversary ceremonies for the 9/11 attacks when President Obama and his predecessor George W Bush are due in the city, along with large crowds.

On September 11, 2001, two hijacked planes hit New York's World Trade Centre, turning the iconic twin towers to rubble, a third plane plowed into the Pentagon and the fourth plane crashed into a field in Pennsylvania.


'Lots of chatter' on jihadi websites ahead of 9/11: Napolitano
    
US intelligence officials have picked up ‘lots of chatter’ on jihadi websites and elsewhere about the impending 10th anniversary of the 9/11 terrorist attacks and authorities are taking them seriously, Homeland Security Secretary Janet Napolitano has said.
    
"We still have lots of chatter out there. And we take every bit of that seriously and are tracking it down," Napolitano said.
    
"In the intel world, there's lots of chatter, and we're taking it all seriously. And should there be something that rises to the level where I have to issue a threat advisory, we will issue a threat advisory," she said at a press briefing.
    
Napolitano said it is not uncommon to see increased chatter before major events.

"We know it's an iconic day to al Qaeda, in part because of what was found at the (Osama bin Laden) compound. So we are preparing accordingly," she said.
     
"I don't want to give those (details) out because I don't want to tell the bad guys exactly what we're doing," Napolitano said.
     
"But I think it's fair to say that in addition to asking citizens to be vigilant and so forth, that we have ourselves leaned forward and have made sure that we are doing all that we can from the DHS perspective."
     
On September 11, 2001, two planes hijacked by al Qaeda terrorists hit New York's World Trade Centre, turning the iconic twin towers to rubble, a third plane plowed into the Pentagon and the fourth plane crashed into a field in Pennsylvania.

(Agencies)