At least 19 people were injured, four seriously, when a Mexican naval ship struck the Brooklyn Bridge on Saturday, New York City mayor Eric Adam says.

The span was spared major damage.

In a scene captured in multiple eyewitness videos, the masts could be seen snapping and partially collapsing as they crashed into the deck of the bridge.

Videos showed heavy traffic on the span at the time of the collision.

The vessel, which was flying a giant green, white and red Mexican flag, then drifted toward the edge of the river as onlookers scrambled away from shore.

Sydney Neidell and Lily Katz told The Associated Press they were sitting outside to watch the sunset when they saw the vessel strike the bridge and one of its masts snap.

Looking closer, they saw someone dangling from high on the ship.

“We saw someone dangling, and I couldn’t tell if it was just blurry or my eyes, and we were able to zoom in on our phone and there was someone dangling from the harness from the top for like at least like 15 minutes before they were able to rescue them,” Katz said.

They said they saw two people removed from the ship on stretchers onto smaller boats.

The Mexican navy said in a post on the social platform X that the Cuauhtemoc, an academy training vessel, was damaged in an accident with the Brooklyn Bridge that prevented it from continuing its voyage.

It added that the status of personnel and material was under review by naval and local authorities, which were providing assistance.

“The Secretary of the Navy renews its commitment to the safety of personnel, transparency in its operations and excellent training for future officers of the Mexican Armada,” it said in Spanish.

The Brooklyn Bridge, which opened in 1883, has a nearly 490-metre main span that is supported by two masonry towers.

More than 100,000 vehicles and an estimated 32,000 pedestrians cross every day, according to the city’s transportation department, and its walkway is a major tourist attraction.

The Cuauhtemoc — about 90.5 metres long and 12 metres wide, according to the Mexican Navy — sailed for the first time in 1982.

Each year it sets out at the end of classes at the naval military school to finish cadets’ training

This year it left the Mexican port of Acapulco, on the Pacific coast, on April 6 with 277 people onboard, the Navy said then.

The ship was scheduled to visit 22 ports in 15 nations, including Kingston, Jamaica; Havana, Cuba; Cozumel, Mexico; and New York.

It had also planned to go to Reykjavik, Iceland; Bordeaux, Saint Malo and Dunkirk, France; and Aberdeen, Scotland, among others, for a total of 254 days, 170 of them at sea.