SANTA FE, N.M. -- Hundreds of law officers helped by helicopters scoured the countryside yesterday for two convicted murderers and five other inmates who escaped from a state prison by pulling a gun on a guard and pole-vaulting over a barbed-wire fence.

Roadblocks were set up around Santa Fe, and state police and National Guard helicopters scanned the landscape after the prisoners' well-planned breakout Saturday night from the penitentiary south of here.

In Jackson, Mich., meanwhile, three inmates imprisoned for life on murder convictions remained at large after they escaped from the state prison.

The New Mexico escape began about 9 p.m. when convicted murderer William Wayne Gilbert, who was out of his cell mopping floors, pulled a gun on a guard at the prison's maximum-security North Facility, authorities said.

Gilbert then used the guard to enter the prison control center, where he shot the lone officer on duty and opened the cell doors of the six other inmates, said corrections officer Robert Greeney.

The inmates, wearing dark-colored winter prison clothing, went through an emergency door in the control center to the roof, where they reached a wall behind the prison, walking along its top before using a pole to vault over a barbed-wire fence.

The prison's guard tower, from which the area is visible, had been staffed only from 7 a.m. to 8 p.m. daily because of financial restrictions, said Corrections Department spokesman Don Caviness.

Gilbert was sentenced to death in 1980 for the slaying of an Albuquerque couple. His sentence and those of the state's four other death row inmates were commuted to life in prison last November by then-Gov. Toney Anaya (D).