New York City ? Rescuers dug through debris Sunday for three people still missing in the rubble and wreckage left when a construction crane toppled like a tree across a city block and killed at least four construction workers.

Among the missing were two workers and a woman who was staying in an apartment at a townhouse flattened by the crane.

“Each passing hour, things get a little more grim,” Fire Commissioner Nicholas Scoppetta said. Twenty-four others were injured, including 11 first responders, said Mayor Michael Bloomberg. Eight remained hospitalized Sunday, officials said.

The crane rose 19 stories and was attached to an apartment tower under construction when it broke away Saturday and toppled like a tree onto buildings as far as a block away.