The fire at 1126 S. 21st St. was reported at 3:45 a.m.

When firefighters arrived there were flames coming out of windows on the first and second floors. Neighbors reported that people and a dog could be in the house.

Fire Chief Steve Hergenreter said an aggressive interior attack and search and rescue effort was launched. No people or pets were found in the house, he said.

The house sustained serious fire damage in the living room, hallway, stairwell and second floor bedrooms.

The cause of the fire is under investigation.

The home’s owner was identified in Fire Department reports as Kevin Johnson, of Kasota, Minnesota.

Hergenreter said the blaze occurred at the end of an exceptionally busy 24-hour period in which the Fire Department responded to two house fires, 18 medical emergencies and handled two long distance patient transfers, one to Iowa City and one to Des Moines.