[UPDATE BELOW] LaGuardia airport is a nightmare tonight as Port Authority police and the NYPD bomb squad investigate an unattended vehicle. It's unclear where the vehicle was abandoned—some reports say a truck was left outside Terminal B—but the NYPD press office confirms that Port Authority police requested the NYPD bomb squad to investigate an unattended vehicle. What we do know is that LaGuardia's Terminal B, and other terminals, have been in lockdown since shortly after 11 p.m. tonight.

One traveler tells us she is stuck at Terminal 2 and the National Guard has shut down the terminal, refusing to allow anyone in or out. The same lockdown is in effect at Terminal B, and travelers getting off flights have been informed they would not be allowed to leave. The scene is being variously described as "utter confusion," a "total mess," and "pandemonium." It appears that many people who were able to leave the terminal are simply walking along the side of the road in search of cabs.

We are getting reports that Terminal B has been reopened as of 12:35 a.m. We will update as we know more.

UPDATE 12:47 a.m.:

Travelers in Terminal B report that the "all clear" has been given and they are being permitted to leave. Here's a photo of what witnesses and media outlets are reporting to be the suspicious vehicle:

And now the desperate late night scramble for a cab begins...

It's worth noting that in the wake of the Chelsea bombing, reports of suspicious packages—and the diligent NYPD investigations that ensue—have spiked dramatically.

UPDATE 1:05 a.m.: An NYPD spokesperson confirms that "the vehicle has been rendered safe and clear, and the Port Authority is investigating."

According to one law enforcement source, the man who abandoned the vehicle is a known livery cab driver.

Update 9:45 a.m.: Port Authority spokesman Joseph Pentangelo tells us the car was impounded and issued a "no parking summons." PAPD detectives' investigation is ongoing.