NEW YORK - The city fire department remains on the scene of an apartment fire on the Upper East Side, one of two fires that broke out overnight in the borough.

Fire officials say flames broke out around 2 a.m. on the fourth floor of a five-story building located at 1562 Third Avenue.

A security guard at a nearby construction site called 911 when he saw the flames, then rushed inside the building to warn people about the fire.

Three people were taken to Lenox Hill Hospital with minor injuries.

Over on the west side, the FDNY says flames broke out on the top floor of a six-story building located at 605 West 141st Street in Hamilton Heights.

The fire spread to part of the roof.

It was declared under control around 2:30 a.m.

One firefighter was taken to the hospital in serious condition.