4 'extremely dangerous' inmates on the loose after overpowering female guards at jail

Ohio authorities are searching for four inmates who escaped a jail after overpowering two female corrections officers.

They were armed with at least one homemade weapon, a shank, when they overpowered the officers and forced open a secured door at the Gallia County Jail in Gallipolis, Ohio, just after midnight on Sunday, authorities said.

The Gallia County Sheriff's Office identified the inmates as Brynn K. Martin, 40, Christopher M. Clemente, 24, Troy R. McDaniel Jr., 30, and Lawrence R. Lee III, 29.

They are considered "extremely dangerous," authorities said.

Investigators have determined that they received assistance from at least one person on the outside, according to the sheriff's office.

Once they gained access to the administrative wing of the jail, they stoles the keys to one of the corrections officer's vehicles and drove about a block away, where another vehicle was waiting for them, Gallia County Sheriff Matt Champlin told reporters at a press conference Sunday afternoon.

That vehicle has since been found in Pennsylvania, Champlin said. Pennsylvania State Police tweeted that they have reason to believe that Clemente is in the area of the Westmoreland Mall in Greensburg.

The U.S. Marshals Service is offering a reward of $2,500 per inmate for information leading to their apprehension, Champlin said.

The female corrections officers were not injured during the escape, he said. They were overseeing the male population because the two male corrections officers who were scheduled overnight called in sick.

The facility is short-staffed and unable to house inmates in individual cells due to the open-room layout that was designed in the 1980s to allow for more housing, Champlin said.

ABC News' Alexandra Faul contributed to this report.