Killers Richard Matt, 48, and David Sweat, 34, sneaked out of the all-male Clinton Correctional Facility in Dannemora sometime between Friday night and early Saturday, with police saying the discovery was made during morning “roll call” and warning the duo should not be approached.

They reportedly left a taunting note behind saying: “Have A Nice Day.”

New York Governor Andrew Cuomo said on Twitter he had toured the daring route the pair took to freedom, posting images of the path the men were believed to have cut to escape.

The pair used power tools to drill through walls and pipes, he said, and left sweatshirts and other clothing in their beds as decoys to make it appear they were still in their cells.

No one has ever previously escaped from the maximum security portion of the prison, which opened in 1845, according to Cuomo.

“These are two dangerous individuals, one was incarcerated for killing a sheriff, so these are dangerous people,” said Cuomo, who canceled a scheduled appearance at the Belmont Stakes horse race to instead travel to the prison.

“And they are nothing to be trifled with.”

He added: “By definition, it was an extraordinary act,”

More than 200 law enforcement officers were deployed in the frantic search, assisted by a variety of tactical support, including K-9 units, SWAT teams and helicopters.

Heavily armed police set up road blocks in an attempt to hunt down the two men.

Matt and Sweat were found missing during a 5:30 am bed check, according to state police.

“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,” authorities said in a statement.

It was unclear whether the men were armed or had received help in plotting their escape.

Richard Matt, 48, is pictured in this handout photo

After cutting through the steel back walls of their cells, they reportedly clambered along a six-foot-high catwalk to access a twisting series of pipes and tunnels, which they also cut their way into.

They then made their way through the pipes and climbed up through a manhole onto a nearby street, The New York Post said.

The strapping Matt, who is six feet tall (1.8 meters) and has multiple tattoos — including a Marine corps insignia on his right shoulder — was serving a sentence of 25 years to life for kidnapping a man and beating him to death.

He also has tattoos on his back with the words “Mexico Forever.”

Sweat, who has tattoos on his left bicep and his right fingers, was serving a sentence of life without parole for killing a sheriff’s deputy.

About 3,000 inmates live at the prison, according to the Village of Dannemora’s website.

David Sweat, 34, is pictured in this handout photo