A man accused of shooting dead a Pennsylvania state trooper has been arrested after eluding capture for six weeks during a massive manhunt through mountains and dense forests, authorities said.

Eric Frein, described in US media reports as a self-trained sniper and survivalist with a hatred of law enforcement, had been hunted after allegedly killing trooper Bryon Dickson and wounding another officer on September 12.

The thirty-one-year old could face the death penalty, prosecutors said, after the operation involving several hundred officers combing the Pocono Mountains ended with his arrest on Thursday.

Frein's capture, about 55km south of where the ambush occurred, may finally shed light on how the suspect was able to stay one step ahead of authorities for 48 days.

"Eric Frein had a mission and that was to attack law enforcement," Frank Noonan, commissioner of the Pennsylvania State Police, told a news conference.

"If he got out of those woods, we were very concerned he would then kill more law enforcement, if not civilians."

Noonan said at this stage there was no indication of anyone else being involved. 

Capital punishment

Prosecutors will seek capital punishment for Frein, who faces a first-degree murder charge and one count of homicide of a police officer, among others, Pike County District Attorney Raymond Tonkin said.

He was jailed without bail after facing the charges in court on Friday.

The manhunt has involved hundreds of officers from state, local and federal agencies, using helicopters, armoured vehicles and sophisticated tracking technology.

In the end, officers from the US Marshals service on a routine patrol captured Frein at 6pm outside an abandoned aircraft hangar at a shuttered resort in Tannersville, Pennsylvania.

Frein, who was on the FBI's most-wanted list, surrendered without incident, officers said.

Police have said the suspect, an expert marksman who dressed like a Serbian soldier in a war reenactment group, held a longstanding grudge against law enforcement but they have provided little evidence.

The sniper was not targeting any individual officer, they said.

The heavy police presence and the aggressive tactics employed during the manhunt rattled many residents of the normally peaceful area of northeastern Pennsylvania, even as the shootings appalled the community.

The region, a popular place for deer hunting, was put off limits to hunters this season, in a big setback to the local economy.

Source: Agencies