A fire broke out inside a 16-story Upper West Side apartment building early Thursday, injuring seven tenants and five firefighters, the FDNY said.

The blaze began around 5:50 a.m. on the third floor of 98 Riverside Drive, near West 81st Street — and firefighters had the flames under control by about 7:10 a.m.

The civilians and firefighters were both taken to local hospitals for non-life-threatening injuries, officials said.

The cause of the fire is under investigation