http://www.foxnews.com/story/0,2933,172594,00.html BALTIMORE One of two tunnels carrying traffic under Baltimore's harbor was closed Tuesday and another was partially shut down in response to what an official said was a security threat. The Baltimore Harbor Tunnel (search) was closed while the Fort McHenry Tunnel was partially closed, with one lane of traffic moving in each direction, said Lt. Col. David Franklin of the Maryland Transportation Authority Police (search). The closures were in response to a threat, a federal law enforcement official said. The official, who spoke on condition of anonymity because of the sensitivity of the issue, did not provide further information about the nature of the threat. More in article link.