Fire crews doused a large blaze at a vacant building about a block away from St. Mary Medical Center early this morning.

The blaze was intense enough that it sparked evacuations in the building next door, although firefighters were able to stop the flames from spreading there, authorities said.

The flames broke out around 2:30 a.m. at a two-story building with empty shops on the first floor and vacant apartments on the second floor, according to authorities.

The first crews to arrive found heavy smoke and fire coming from the second floor, according to Battalion Chief Jeff Ohs. Right away, they called for reinforcements by designating it a second-alarm fire, according to Ohs.

A total of about a dozen fire engines, ambulances, trucks and other vehicles ultimately responded to the blaze, which they had knocked down within about half an hour, Ohs said.

The building is right next to a newer apartment development on Long Beach Boulevard just south of 12th Street. The flames set off fire alarms at the apartments, prompting evacuations for a while, according to Ohs.

The building that caught fire has been slated for demolition or renovation, according to Ohs, who said there’s been problems with squatters at the property.

However, nobody was hurt in the blaze, and investigators are still trying to determine how it started.

City News Service contributed to this report.