CHARLOTTE, N.C. — Three firefighters were sent to the hospital after battling a house fire early Thursday morning, according the Charlotte Fire Department. Investigators say they believe the fire was intentionally set.

The two-alarm fire happened at a home on Grimes Street, and one firefighter called for mayday over their radio, officials said.

All three firefighters suffered serious injuries, but are expected to be okay, the fire department said on X. The injured firefighters were released from the hospital by Thursday afternoon, according to the fire department.

The department shared videos of the blaze as crews worked to put it out. Charlotte Fire didn’t share whether residents were inside the home, but said it took about an hour to put out.

Videos show flames and smoke coming from a two-story house as crews worked to put the fire out.