Terrorists had allegedly planned to attack the PATH rail system that links Manhattan and New Jersey under the Hudson river, according to Mark Mershon, assistant director-in-charge of the FBI New York field office.
US authorities said the plan was still in the planning stages and that the suspects had not done any reconnaissance or gathered any materials with which they could to carry out the attack.
An FBI official said none of the suspects had ever visited the US.
"This is a plot that would have involved martyrdom, explosives and certain of the tubes that connect New Jersey with Lower Manhattan. We're not discussing the modality beyond that," Mershon told a news conference on Friday.
Mershon(C): "This is a plot that
would have involved martyrdom"
Initial newspaper reports of the plot had said it was to target the car-carrying Holland Tunnel with a bomb.
US authorities worked with intelligence agencies from six different countries to disrupt the plot.
The FBI described the alleged plotters as a "terrorist network".
Mershon said: "We believe we have what I'll call eight principal players. And that we have them largely identified." He added: "Some are in custody, one of those has been charged formally in Lebanon."
Lebanese sources in Beirut said they had arrested Assem Hammoud, also known as Amir al-Andalousi, in April acting on information provided by the FBI.
"After questioning he confessed ... that he was planning to travel to Pakistan for four months training and that the date for the attack was decided to be late in 2006," Lebanon's interior ministry said in a statement.
The suspect told investigators he was acting "on a religious order from (al-Qaeda leader Osama) bin Laden and said 'I am proud to carry out his orders'," a security source said.
The plot was uncovered by monitoring internet chat rooms, the New York Daily News reported.
Initial reports said the Holland
road tunnel was the target
The FBI and the department of homeland security said in a statement the "terrorist network" was linked to al-Qaeda, and the Daily News said it was linked to Abu Musab al-Zarqawi, the al-Qaeda leader in Iraq recently killed by US forces.
It was the second recent plot authorities have said they broke up in the early stages, following the arrest of seven people last month for allegedly planning an attack on the Sears Tower in Chicago. One official described that plot as being "more aspirational than operational".