Authorities have disrupted planning by foreign terrorists for an attack on New York City tunnels, two law enforcement officials said Friday. FBI agents monitoring Internet chat rooms used by extremists learned in recent months of the plot to strike a blow at the city's economy by destroying vital transportation networks, one official said. Lebanese authorities, acting on a US request, have arrested one of the alleged plotters, identified as Amir Andalousli, the other official said. The officials spoke on condition of anonymity because the investigation is still under way. The planning for the tunnel attacks was first reported by the New York Daily News in its Friday edition, the first anniversary of the attacks on the London transportation system that killed 52 people. It was unclear how far along the planning was. But the FBI, in a brief statement, said, "At this time, we have no indication of any imminent threat to the New York transportation system or anywhere else in the United States." The Daily News reported that the plotters wanted to blow up the Holland Tunnel, the southernmost link between Manhattan and New Jersey, in the hopes of flooding New York's Financial District. The desired effect would be akin to the flooding that ravaged New Orleans in the wake of Hurricane Katrina, the newspaper said. However, all of lower Manhattan is above the water level, so it is unclear how flooding a tunnel could possibly have affected higher ground.