JAMESTOWN (AP) - An early morning fire at a three-story apartment building was deliberately set - the second suspicious apartment fire in the city in a month, officials say. No serious injuries were reported.

The blaze Thursday morning was reported at about 5 a.m., and was believed to have started in the street-level entry of the building, blocking that exit.

"There was no heat source where the fire started and no reason for a fire to have started in that area," Fire Chief Bert Gray said.

Firefighters used ladders to rescue people from the third floor and one woman handed her young child to another person from a second-story window before crawling out to safety, Gray said

"I'd say the window was six to eight feet from the ground," Gray said. "Fortunately, nobody was hurt."

One person was given oxygen at the scene and three people were taken to a hospital to be checked out, Gray said.

Authorities have been looking into more than half a dozen unsolved fires in Jamestown over the past five years, though they have said there is no evidence to connect them. They said a May 29 apartment blaze, which caused an estimated $65,000 in damage, is considered suspicious.

Gray and Fire Capt. Jim Reuther said the apartment fires have some similarities.

"It's too early to say if they are related," Gray said. "But they are certainly under suspect."

Gray said 19 people lived at the 12-unit apartment complex in northeast Jamestown that burned Thursday.

"It's going to be quite a while before anyone can live there," Gray said. "Heat and smoke went through the entire building."