This story has been updated.

UPDATE 4:21 p.m. EDT: Authorities say Richard Matt and David Sweat, two convicted murderers, used power tools and a series of tunnels to escape Saturday from Clinton Correctional Facility. Matt and Sweat cut through the walls in their cells, scaled a cat walk and escaped through a manhole cover that was about a block away. New York Gov. Andrew Cuomo went to the prison to "retrace" the pair's footsteps in what he called an "elaborate plot" at a news conference held at the prison this afternoon. Cuomo added it's possible the inmates followed heating pipes and the prison's inner workings to escape.

The two were still at large when this story was updated.

.@NYGovCuomo outside cell of one of escaped inmates at Clinton Correctional facility: pic.twitter.com/QbTq0xOqP6 — Gareth Rhodes (@garethtrhodes) June 6, 2015

Original story below.

The New York State Police took to social media Saturday to ask for the public’s help in finding two prisoners who are believed to have escaped from the Clinton Correctional Facility in Dannemora, New York. The facility called the state police Saturday at 5:45 a.m EDT, indicating two prisoners were unaccounted for during a bed check 15 minutes earlier, according to a post on the agency’s verified Facebook page. It posted the same message on its Twitter account, asking users to share the message.

Police say they are searching for Richard Matt, 48, and David Sweat, 34. Both are white men, according to the post, which included their descriptions. They are considered to be dangers to the public. Their descriptions and instructions about what to do should you spot them appear in the post, relevant portions of which are quoted below:

Richard Matt, 48 years old, a white male, 6’ tall, 210 pounds, with black hair and hazel eyes. He has tattoos on back “Mexico Forever,” a heart on his chest and left shoulder, and a Marine Corps insignia on his right shoulder. David Sweat, 34 years old, white male, 5’11” tall, 165 pounds, brown hair and green eyes. He has tattoos on his left bicep and his right fingers. Both are considered to be a danger to the public. If located, DO NOT approach them. Contact 911 or the New York State Police immediately at (518) 563-3761. Anyone in the Dannemora area should contact the New York State Police if they saw or heard anything early this morning, or find that they have a vehicle which is unaccounted for.

The state police also detailed the men's sentences, noting, “Matt is serving a sentence of 25 years to life following his conviction in Niagara County for three counts of murder, three counts of kidnapping, and two counts of robbery after he kidnapped a male victim and caused his death by beating him on December 3, 1997.” And the police said, “Sweat is serving a sentence of life without parole following his conviction in Broome County for one count of murder 1st degree after he caused the death of a Broome County sheriff’s deputy on July 4, 2002.”

Built in 1844, the Clinton Correctional Facility is an all-male prison that houses about 3,000 inmates. It is located in Clinton County.