US prison break: Jail officer who passed hamburger to killers arrested

A second prison worker was arrested and charged today over the escape of two convicted killers weeks ago from a maximum-security New York jail, with police warning they are likely armed and dangerous.

Richard Matt, 49, and David Sweat, 35, used power tools to cut their way out of their cells at the Clinton Correctional Facility before dawn on June 6 in a spectacular prison break likened to a Hollywood movie.

The escape sparked a huge manhunt with more than 1,000 agents backed by sniffer dogs and helicopters deployed to find the men, who have reportedly been spotted in several locations in recent days in upstate New York.

Corrections officer Gene Palmer, 57, was charged with promoting prison contraband, two counts of tampering with evidence and one count of official misconduct, Major Charles Guess of New York State Police said in a statement.

Palmer allegedly helped smuggle tools and other banned items hidden in hamburger meat, said Clinton County District Attorney Andrew Wylie, according to ABC News.

Another prison worker, Joyce Mitchell, had already been charged with facilitating the escape by providing hacksaw blades and drill bits to the pair, again hidden in hamburger meat, Wylie told local media.

Palmer's lawyer said while the corrections officer delivered the meat to the prisoners, he was not aware the packages were stuffed with contraband items.

"Mr Palmer did not know what was inside the package, he had no knowledge beforehand that there were any kind of tools inside," Andrew Brockway told CNN.

"The only mistake he made was trusting Joyce Mitchell."

Mitchell's husband told NBC News that his wife enjoyed "attention" and attempted kisses from Matt when their marriage hit a rough patch, but said his wife denied having sex with either inmate.

Meanwhile the search continued in a 194 square kilometer area within Franklin County in upstate New York, and authorities said the escapees are probably armed given the surrounding area is so heavily stocked with weapons and ammunition.

"Just about every cabin or out building in the north country has one or more shotguns or weapons," Guess told reporters.

"We have, since day one, operated under the belief that these men are armed. They're extremely dangerous, they're cunning, why wouldn't they try to arm themselves?"

There have been widespread reports that a shotgun is missing from a remote cabin where DNA traces and a bloodied sock indicate they were most likely holed up as late as Saturday morning.

"They put an inordinate amount of weapons and ammunition and other tools in these shared seasonal hunting camps and cabins," Guess said.

The terrain in the search parameters is a combination of hills, heavy forest and dense vegetation, with rivers and thick bogs complicating the manhunt.