NEW YORK (AP) — Four New York City firefighters suffered minor injuries Tuesday when part of a ceiling collapsed on them as they were battling a blaze at an upper east side restaurant, authorities said.

The fire started at about 5 a.m. in a restaurant on the ground floor of a five-story apartment building on First Avenue and spread to the floors above, a fire department spokesperson said.

More than 160 firefighters responded to the fire, which was not yet under control as of 7:30 a.m., the spokesperson said.

The four firefighters who were injured in the partial ceiling collapse were treated at a hospital, authorities said. No other injuries were reported.

The cause of the fire was under investigation.