PHOENIX — Police were using helicopters and dogs Saturday to search for three convicted murderers who escaped from a northwest Arizona prison, kidnapped two semi-truck drivers at gunpoint and used the big rig to flee.

Department of Corrections spokesman Barrett Marson said the men escaped Friday evening by cutting a hole through a perimeter fence at the medium-security Arizona State Prison in Golden Valley, about 90 miles southeast of Las Vegas. They should be considered especially dangerous because of the nature of their convictions, he said.

Officials identified the escapees as Tracy Province, 42, who was serving a life sentence for murder and robbery; Daniel Renwick, 36, serving 22 years for second-degree murder; and John McCluskey, 45, serving 15 years for second-degree murder, aggravated assault and discharge of a firearm.

Province is from Illinois, and Renwick and McCluskey are from Arizona.

Flagstaff police Sgt. James Jackson said a woman identified as Casslyn Mae Welch, 44, met the men and helped in their escape, and at about 5 a.m. Saturday, the group kidnapped two drivers of a semi-truck in Kingman and forced them at gunpoint to drive two hours east to Flagstaff.

The group left the drivers, unharmed, in the truck at a stop just off Interstate 40 and then fled in an unknown direction, Jackson said.

"The truck drivers were lucky to get away unscathed," he said. "I mean, they've been convicted of murder and they're escaping from prison."

Authorities urged anyone with information on the escaped prisoners to use caution and call police immediately.

The escapees were last seen wearing orange prison jumpsuits.

Management and Training Corp. of Centerville, Utah, operates the prison. The company operates seventeen correctional facilities in Texas, New Mexico, Arizona, California, Idaho and Ohio, according to its website.