Following a collision with a container ship on Tuesday, a significant bridge in the US city of Baltimore nearly completely collapsed, sending several cars and as many as 20 people falling into the harbor below.

In a dramatic video, a 300-meter boat struck one of the Francis Scott Key Bridge’s footings, causing the steel-framed building to collapse into the Patapsco River.
As the bridge bends and crashes in places, lights from what appear to be cars can be seen on the road surface. The third tranche cantilevers upward before collapsing into the water.

There are also a few minor explosions visible during the quick collapse.

According to Kevin Cartwright of the Baltimore Fire Department, “Unfortunately, we understand that there were up to 20 individuals who may be in the Patapsco River right now as well as multiple vehicles,” CNN reported.

“We understand that there could have potentially been a vehicle, a tractor trailer or a vehicle as large as a tractor trailer on the bridge at the time that it collapsed.”

The video appeared to show the ship going dark twice in the final seconds before the crash, and thick black smoke billowing from the funnel—possibly a sign of engine activity.

Following the collision, which occurred at around 1:30 am (0530 GMT), a massive emergency response was launched, with first response vehicles clogging the shoreline.

According to Cartwright, divers were searching for survivors in the water.

According to CNN, the water was about 48 degrees Fahrenheit (8.8 degrees Celsius), which made search and rescue operations more difficult and reduced the amount of time that anyone in the water could survive.

Images captured at the scene display bridge debris resting on the ship’s deck, which was piled several high with containers.