A massive 4-alarm fire broke out at a New York City church

A massive fire broke out at the Serbian Cathedral of Saint Sava in New York City on Sunday evening.

It is unclear whether anyone was in the building or how the fire started.

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A side of the church, which is located at 20 W. 26th St. in Manhattan, was in danger of collapsing, according to PIX11 News.

The fire broke out around 6:49 p.m., according to the FDNY. It quickly spread to three alarms, and by 8 p.m. the fire had spread to four alarms.

The FDNY was on the scene with about 170 firefighters.

The number of alarms in the FDNY fire-alarm rating system corresponds to the number of firefighters required to respond to the fire. For a two-alarm fire, the FDNY dispatches 25 units and 106 firefighters; a three-alarm fire means 33 units and 138 firefighters; a four-alarm fire means 39 units and 168 firefighters, according to Slate.

WATCH MORE: Raw footage from the scene