HARTFORD, Conn. (AP) _ Two inmates injured in a fire at the state's highest security prison Wednesday night set the blaze themselves, an investigation indicates.

It wasn't immediately clear what the two men used to start the fire in their cell at the Northern Correctional Institution or how they got the materials, Department of Correction Capt. Heather Ziemba said Thursday. Smoking is not allowed in Connecticut prisons.

Magazines, papers, boxes, mattresses and bedding were set ablaze. Guards spotted the fire during routine rounds in a unit housing about 50 inmates, including residents of Connecticut's death row. The fire did not spread beyond the cell.

Inmate Alex Sostre was treated for smoke inhalation. He is awaiting trial for the Jan. 23, 1999, fatal shooting of a police officer. His cellmate, Pedro Poupart, 18, who is serving 17 months for assault on an officer, was being treated for minor burns.

Guards used extinguishers to douse the flames, and all the inmates were moved temporarily to another area of the prison. One inmate who refused to be moved was doused with pepper spray, but no one else was injured, Ziemba said.