MINNEAPOLIS (WCCO) – A fire in St. Anthony caused a house’s main floor to collapse into the basement Sunday morning, authorities said.

Firefighters responded to the fire, which flared up in a home on the 3600 block of Harding Street Northeast, just after 11: 20 a.m.

When firefighters arrived, they found heavy smoke and intense heat. They said battling the flames was difficult.

No one, including firefighters, was hurt in the fire, authorities said.

Crews battled the fire for more than two hours. They said the house sustained significant damage.

The fire is currently being investigated by the Hennepin County Fire Investigation Team. No cause has yet been determined.