Police searching for two escaped murderers are said to be moving in large numbers to an area in south-western New York.

New York State Police confirmed on Saturday (20 March) that they were zeroing in on Allegany County, New York, as the manhunt for Richard Matt, 48, and David Sweat, 35 increases momentum.

The fugitives escaped from the Clinton Correctional Facility in Dannemora, 20 miles (32km) from the Canadian border on 6 June, after drilling through the steel walls of the prison.

New York State Police say they now have a confirmed sighting of the wanted men in Friendship, a small town near the border with Pennsylvania.

The New York Times, citing a law enforcement official, reports that a woman saw two men walking out of a wooded area. One of the men then fled back into the woods, and the other pulled his hooded sweatshirt over his head.

CNN reports that investigators found tracks after a phone tip-off, and are trying to determine whether they belong to the escapees.

Responding officers were asked at one point to maintain radio silence and reporters were asked to leave the search area which police described as a "hot spot."

Police were also pursuing other possible sightings of the two men in Steuben County, about 45 miles east of Friendship.

New York State Police confirmed the sightings in a news release on Friday (19 June) which stated: "Witnesses spotted two men on June 13 walking near the Gang Mills rail yard on Rita's Way in the town of Erwin," police said. "The next day, two men with the same description were spotted walking along County Route 115 in the town of Lindley, heading toward the Pennsylvania Border."

The sightings came from two separate individuals, police spokesman Beau Duffy told CNN on Saturday.

Police have urged people living in the Allegany County area along the New York-Pennsylvania border to be on alert for Matt and Sweat, both of whom have killed in the past and are regarded as dangerous.

"Do not approach, as both are considered to be very dangerous," the state police news release warned.

Matt, was serving 25 years to life for three counts of murder, kidnapping and robbery for the torture and dismemberment of his former boss in 1997. Sweat was serving a life sentence without the possibility of parole for the murder of a sheriff's deputy in 2002.

The U.S. Marshals Service has added Matt and Sweat to its list of the 15 most wanted fugitives and offered a $50,000 reward for information leading to their capture.

The list "is reserved for the worst of the worst," said U.S. Marshals Service Director Stacia Hylton. "There is no question David Sweat and Richard Matt fall into this category."

Authorities warned on Friday that the search could take some time as the massive manhunt enters another week.

"We're configured now for a rapid response," New York State Police Maj. Charles Guess said at a news conference. We'd like nothing more than to place them into custody today. ... However, we're also geared for the long haul, the state police and our partners. ... We're no strangers to lengthy months and yearlong investigation."

As many as 800 law enforcement officers have participated in the manhunt, which has cleared nearly 200 abandoned buildings, hundreds of occupied homes and more than 600 miles of rural trails, officials said.

"We're not going anywhere," Guess said. "Our plan is to pursue these men relentlessly until they are in custody."