NEW YORK - A crane mounted to the side of a skyscraper under construction toppled and smashed into a block of apartment buildings, killing at least four people and setting off a scramble for survivors in the towering piles of rubble.

Mayor Michael Bloomberg said at least 10 people were injured in one of New York City's worst construction accidents in recent memory. The dead are all believed to be construction workers.

"It is a tragic event," Bloomberg said.

The big, white crane stood at least 19 stories high and demolished parts of several buildings as it fell. A four-story brownstone was completely pulverized by the falling wreckage, and three buildings were damaged.

A delicate rescue operation was under way to free anyone still trapped in the rubble. One man was trapped inside the collapsed townhouse for 3 1/2 hours before firefighters rescued him.

Fire Commissioner Nicholas Scoppetta said the rescue was "a painstaking hand operation, as we try to remove the rubble so we don't cause further collpase or injure anyone who may still be in that building." He said the operation would continue all night if necessary, including the use of search dogs and thermal-imaging and listening devices.

The collapse created a virtual war zone on an affluent block of Manhattan: Cars were overturned and crushed. A huge dust cloud rose over the neighborhood. Rubble was scattered everywhere and piled several stories high.

The catastrophe comes amid a building boom in New York City and follows a spate of construction accidents in recent months, including some involving cranes.

Read the full report in Sunday's edition of The Citizen.