The four are charged with planning to detonate millions of litres of highly flammable jet fuel at the airport, but the three arrested so far have denied it.

 
'Indirect' ties
 
John Miller, an FBI assistant director, told US media that the four had "as far as we know, no direct ties to al-Qaeda".

 

But he said the movement's "propaganda" aimed to inspire home-grown plotters.

 

Jamaat al-Muslimeen is "a group that's been engaged in violence, they've taken hostages", he said, adding that "home-grown extremists" who are "inspired through the internet ... can pop up anywhere".

 

Blowing up the airport's fuel storage tanks would have led to massive losses [EPA]

Miller said the priority was to locate the source of funding for the group which was actively searching for explosives and had "done up to four surveillances".

 

The air traffic and security level at the airport have remained unchanged.

 

Killing Kennedy

 

The suspected plotters sought to blow up the airport's jet fuel tanks and part of the 64km pipeline feeding them from New Jersey, also destroying surrounding residential areas.

 

The suspects include a former cargo handler at the airport, Russell Defreitas, an American citizen, and Abdul Kadir, a former member of Guyana's parliament.

 

"Any time you hit Kennedy, it is the most hurtful thing to the United States," Defreitas said in one recorded conversation.

 

"To hit John F Kennedy, wow ... they love John F Kennedy like he's the man ... if you hit that, this whole country will be mourning. You can kill the man twice."

 

Abdul Kadir and Kareem Ibrahim, a Trinidad citizen, were arrested in Trinidad on Friday and Saturday respectively.

 

'Scale of 9/11'

 

The alleged plot was uncovered barely three weeks after another alleged "home-grown" terror plan was uncovered with the arrest of six suspected Islamic radicals on charges of conspiring to attack the Fort Dix army base in New Jersey.

 

The plot was foiled with the help of an informant who recorded conversations with the suspects, some as recent as last month.

 

Officials said the plot began in the US and spread to Trinidad and Guyana.

   

FBI officials said the cell had shown unusual persistence, seeking finance and expert advice and gathering photographic and video surveillance as well as satellite photographs.

 

Evan Coleman, a terrorism analyst, said the plot was "designed to kill thousands of people, to disrupt the US economy and to cause damage on the scale of 9/11".