NEW YORK (CBSNewYork) – The George Washington Bridge has reopened after reports of a suspicious device on the span linking New York and New Jersey shut down traffic for hours.

According to police sources, the Port Authority Police Department called in the Bergen County Bomb Squad to help with an investigation into a possible threat on the bridge.

Traffic on the upper level was initially suspended due to police activity, but authorities later closed the lower level around 10 p.m.

The stoppage on the lower level lasted only a few minutes however, and traffic resumed in both directions around 10:45 p.m.

Shortly after 11 p.m. traffic on both levels was opened for the countless drivers trapped on the upper span.

Earlier in the night, a heavy police presence was seen on the bridge and drivers posted on social media that authorities are ordering people to “stay in your vehicles.”

Commuters told CBS2 they were stuck on the ramps leading onto the bridge’s upper level and could not get off while the police continued their work.

Sources told CBS2 late Thursday night the device was not a bomb, but a pipe with caps on the ends which made it look like a pipe bomb.

CBS2’s Valerie Castro and Ali Bauman reported heavy delays on the span around 11 p.m. after traffic was reopened.

Stay with CBS New York for the latest on this developing story