Both victims were alone inside the structures, authorities said.
Separate fires late Friday afternoon claimed the lives of two men, one in Hubbard Township and one in Warren.
In Hubbard Township, a man who a neighbor said was staying at his sister's house to watch her two dogs was found dead after firefighters responded to a call that smoke was billowing out of the home at about 4:45 p.m. Friday.
"I was taking my dog out for a walk and I saw smoke coming out of the kitchen window," said Shirley Eckley, who lives next door to the home at 1777 Kokomo Drive. "I said, 'Whoa, that's too much,' and I ran back and called 911."
Hubbard volunteer firefighters did not identify the victim, but Eckley said the man's first name is Charles, of Youngstown, and that he is the brother of Anita Whitley, who owns the home with her husband, John. Authorities said the man appeared to be in his 40s or 50s but did not release a cause of death pending an autopsy.
Both dogs also perished.
Eckley said the Whitleys were visiting their son at Ohio Northern University. She said Anita Whitley called her after she was contacted by the fire department.
"She called and I said, 'What about the dogs?' and she said, 'My brother is there watching them.'" Eckley said. "My heart just about dropped. It's tragic. He was a nice man."
A state fire marshal is aiding in the investigation of the blaze, and a fire department spokesman said the Trumbull County coroner would rule on the cause of the death.
Meanwhile, firefighters in Warren were trying to determine the circumstances of a fire that killed a man at 1176 Adelaide Ave. S.E.
Firefighters received the call at 5:14 p.m. Friday and found the man, whom firefighters had not identified as of late Friday, on the first floor of the two-story brick residence, firefighter Mike Loftus said. The victim was alone in the building and was not the owner of the structure, Loftus said.
As firefighter John Jerina worked his way through his search of the building, something knocked off the mask to his air supply and he suffered smoke inhalation, Loftus said. Jerina was treated at St. Joseph Hospital and later returned to duty.