A high-rise crane partially collapsed in New York's busy Midtown area of Manhattan on Wednesday, slamming into an adjacent building and sending concrete debris crashing to the street.

Four civilians suffered minor injuries when the construction crane's arm collapsed shortly before 7:30 am (1130 GMT) after a fire broke out in its operating car, officials said.

Dramatic video footage posted on social media showed the arm smashing into a glass skyscraper across the road as residents ran for their lives to escape the falling debris.

Mayor Eric Adams said the accident could have been much worse.

"We were extremely lucky this morning," he told reporters.

New York City Deputy Fire Chief Joseph Pfeifer said the crane was lifting 16 tons of concrete when its cables became weakened by the blaze.

He said the crane operator saw the fire and tried to extinguish it but the flames overwhelmed him and he had to leave the crane.

"The crane operator was able to get out and is safe," Pfeifer told reporters.

The fire department said it was investigating the incident which occurred on 10th Avenue near the Hudson Yards development on the west side of Manhattan.

In 2016, a crane collapsed in Lower Manhattan during wind gusts and falling snow, killing one person.