Fire reported early Monday at former UMB Bank building in downtown Kansas City, Kansas

A fire reported inside a former bank building in downtown Kansas City, Kansas, is under investigation.

Members of the Kansas City Kansas Fire Department responded to initial reports of a blaze just before 5:20 a.m. Monday, said Assistant Chief Scott Schaunaman, a spokesman for the department.

The fire was reported in a building on the southwest corner of North 6th Street and Minnesota Avenue, just a block from KCKFD headquarters. Firefighters reported heavy smoke from three of the four sides of the two-story commercial building that used to house a UMB Bank.

When crews arrived, they had to remove a steel door to enter the building, Schaunaman said. Once inside, they noticed fire on the second floor but couldn’t get to it because the roof had collapsed.

Firefighters immediately evacuated and attacked the blaze from outside, he said. There was a fear that the fire could spread to an adjacent high rise.

“Because of (firefighters’) actions, that kept the second building from catching on fire,” Schaunaman said, “and if that would’ve happened that would’ve been a huge problem.”

Both buildings were vacant, and no injuries were reported, he said.

The cause of the fire is under investigation, but officials believe it started on the second floor.

The Star’s Anna Spoerre contributed.