Fire tore through the top floor of 40 E. 19th St., officials said. View Full Caption DNAinfo/Trevor Kapp

UNION SQUARE — More than 100 firefighters battled a blaze that tore through the top floor of a Union Square building Thursday morning, officials said.

The fire erupted inside 40 E. 19th St., near Park Avenue South, about 4:40 a.m., an FDNY spokesman said.

About 106 firefighters brought it under control by 5:50 a.m., officials said.

There were no reported injuries, officials said.