The men used power tools to drill through the walls of their cell, officials said

Two men – convicted on four counts of murder between them – managed to escape from the maximum-security portion of a New York prison after drilling through steel walls and slipping through a network of underground tunnels for more than a city block before emerging from a nearby manhole, authorities said.

The disappearance of Richard Matt, 48, and David Sweat, 34, is reportedly the first escape from the maximum-security portion of Clinton Correctional Facility in Dannemora, New York, in its history.

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They left a parting message, according to the governor’s office: A Post-It note was found next to a hole cut in a pipe with a racist caricature of an Asian man wearing a triangle hat and, beneath him, the caption “Have a nice day!”

“These are dangerous people,” New York Gov. Andrew Cuomo said at a news conference, according to CNN. “They are nothing to be trifled with.”

The manhunt includes more than 200 law enforcement officials, according to CNN; and it continued in full force Sunday morning, according to The New York Times.

Cuomo described the escape plan, about which much is still unknown, this way: “It was elaborate, it was sophisticated. It involved drilling through steel walls, steel pipes.”

At which point, Cuomo said, the pair followed a catwalk “down an elaborate maze of pipes into tunnels and exited a series of tunnels at the manhole cover” and were free.

Matt and Sweat had side-by-side cells and were somehow able to obtain power tools in order to cut through the walls that surrounded them; and were able to perform this work without word of it reaching the guards, authorities said according to The New York Times.

They were last seen at 10:30 p.m. Friday, and managed to trick the guards overnight by arranging material in their bunks to look “like people were sleeping … with these sweatshirt hoodies on,” Cuomo said.

Sweat is serving a life sentence without parole following his conviction for one count of first-degree murder in the 2002 death of a sheriff s deputy, state police said in a Facebook post.

He is described as “5’11” tall, 165 pounds, [with] brown hair and green eyes. He has tattoos on his left bicep and his right fingers.”

Matt is serving a sentence of 25-years-to-life following his conviction for three counts of murder, three counts of kidnapping, and two counts of robbery, following the 1997 kidnapping and beating death of a male victim, state police said.

He is described as “6 [feet] 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,” state police said.

Both men should be considered extremely dangerous, state police said.

Anyone with information about their whereabouts is asked to call 911 or the New York State Police immediately at 518-563-3761.