Crews are investigating the cause of a 3-alarm fire in Brooklyn early Sunday morning.

The FDNY says the flames broke out shortly after 7 a.m. on the second floor of a  two story mixed-occupancy building on Utrecht Avenue near 85th Street in Bensonhurst.

Firefighters brought the fire under control by 9:30 a.m.

No injuries have been reported so far.

Because of the fire, subway service on the northbound D subway line was affected. Passengers were being advised to take buses and allow for additional travel time.

For the latest subway information, go to mta.info.