Plumes of thick, black smoke billowed from the Battery Maritime Building at 10 South Street in Lower Manhattan on Saturday afternoon after a fire started in an air conditioning unit on the building's roof.

The FDNY is still working to determine what caused the air conditioning unit to go up in flames. The fire, which broke out shortly before 4 p.m., had reportedly spread into a nearby heavy machinery room. It was brought under control less than an hour later.

In addition to ferries that shuttle visitors to Governors Island, the building is home to Casa Cipriani, a private hotel and membership club.

The blaze did not result in any injuries but caused delays in ferry service between Lower Manhattan and Governors Island. Although passenger-only ferry service has since resumed, ferry passengers should still expect residual delays.

The Governors Island Ferry Waiting Room remains closed until further notice.

This is a developing story.