According to the NY Post
, Port Authority police increased security after learning of a terrorist threat "advising them to be on the lookout for a fuel-filled tanker meant to explode prior to a secondary blast designed to decimate any first responders... The chilling warning was read at roll call for four police commands - cops assigned to the Holland and Lincoln Tunnel; the George Washington Bridge; and also the Staten Island command, which incorporates the Bayonne and Goethals Bridge and the Outerbridge Crossing, a source said."
The alleged threat claims "all crossings" would be in jeopardy and is "being treated as credible, that some type of tanker will explode causing us to respond... At some point during the response, a second explosion [will occur] causing injury to all first responders to this incident." No date or time was given for this supposed incident, but a fuel tanker from Canada may be involved.
The source told the Post that the information came from a prisoner in Afghanistan. However, Police Commissioner Ray Kelly "insisted he was unaware of any specific terrorist threat that had been received by the department targeting the area’s bridges or tunnels" and a Port Authority official said, "It’s a totally unsubstantiated threat," and suggested the threat was mentioned to "[rally] the troops to be vigilant."
Back in 2006, there was an alleged terror plot aimed at the city's tunnels—an FBI official said the plot involved "martyrdom, explosives and certain of the tubes connecting New Jersey and Lower Manhattan."