Minneapolis fire officials are working to determine what caused an early morning fire at a business on Thursday.

According to the city’s fire department, crews were called to a two-story building on the 300 block of East Lake Street around 4:15 a.m. When crews arrived, they found smoke on the second floor and sprinklers going off.

Flames were eventually found in a second-floor closet and quicky extinguished.

No one was found during a search of the building, and no injuries were reported.

The fire department says multiple second-floor windows had to be broken in order to ventilate the building, which will now be boarded up.