Two murderers escaped from a maximum-security prison Monday by breaking a hole in the concrete ceiling of their cell and lowering themselves down the side of the building on bedsheets, officials said.

Guards at the Elmira Correctional Facility (search) discovered the inmates were missing during a routine count at 6:30 a.m., said Jim Flateau, a spokesman for the state Department of Correctional Services.

Guards later found tied-together sheets that led down an outside wall of the four-story cellblock.

The inmates, who lived on the top floor, apparently used a sledgehammer to break through the ceiling, then crawled through a ventilation duct and escaped to the roof, prison union officials said.

The union officials said the sledgehammer was probably stolen from one of several construction projects inside the building.

Timothy Vail, 35, was serving 49 years to life for the 1988 rape and murder of a pregnant secretary. Timothy Morgan, 26, was serving 25 years to life for the 1998 murder of a cab driver.

Eighty to 100 law enforcement officers using police dogs and helicopters patrolled the highways and set up roadblocks in a search for the escaped convicts.

The FBI was contacted in case the men crossed the Pennsylvania state line, less than 10 miles from the prison.

The last escape from a maximum-security prison in the state was in 1994 at the Shawangunk Correctional Facility (search) in Wallkill. Three convicted killers were found bloody and bruised hours after climbing over a razor-wire fence.