A retaining wall at a construction site where blasting work was being done collapsed Wednesday night, forcing several hundred residents to evacuate a nearby apartment building. No injuries were immediately reported.

The wall had been installed to protect the neighboring apartment building on Manhattan's Upper West Side, the city Department of Buildings said in a statement late Wednesday. The wall's fall exposed part of the apartment building's foundation, but the building showed "no signs of distress," the agency said.

Preliminary reports indicated the blasting may have caused the collapse, although authorities were still investigating, the Buildings Department said.

The Buildings Department halted work at the construction site, except for work required to bolster the wall. Heavy construction equipment was being used to dig up earth and put it at the bottom of the wall.

None of the residents of the 288 apartments at 784 Columbus Ave. had been allowed to return home early Thursday, said city Office of Emergency Management spokesman Andrew Troisi. It wasn't clear when they would be allowed back in the building.

The Buildings Department said it expected to order 16 apartments to remain evacuated until they were safe to re-enter.