NEW YORK (AP) — A crane standing about 15 stories high toppled with a roar at a construction site and smashed into a block of apartment buildings Saturday, killing at least two people, authorities said.

The collapsing crane demolished parts of several buildings on Manhattan's East Side and appeared to have pulverized one small, brick apartment building.

Fire Department officials said at least two people were dead. A rescue operation was under way and it was unclear whether anyone was trapped in the rubble.

Nearby residents reported hearing a terrible roar as the structure detached from a large building under construction.

"First I heard a rumble, and it increased, and then it increased," said Bill Reilly, who lives a block away. "It continued building in strength until there was a final vroom! It shook the six-story brick building that I live in."

The crane split into pieces as it fell. Part of it came to rest against an apartment tower, smashing into its upper floors. That building and others in the area were evacuated. Another piece of the crane hit other buildings on the block, ripping away walls and ceilings and crushing the small brick building.

Witnesses reported a strong smell of gas in the area on 51st Street near 2nd Avenue .

Ben Galati, 54, said he was in the basement of a high-rise apartment building across the street where he is a doorman.

"I heard a rumble outside. I said 'Let's get out of here!' And then the crane came down. A split second later, I heard an explosion," he said.