Authorities arrested the man they believe responsible for the recent bombings in New York and New Jersey after a swift manhunt culminating in a shootout that wounded the suspect and two officers.

Prosecutors charged Ahmad Khan Rahami, a 28-year-old naturalised US citizen and Afghanistan native, with five counts of attempted murder of a law enforcement officer. He is expected to face further charges in the bombings that set the New York region on edge over the weekend.

Law enforcement and New York City officials said that they do not believe Rahami operated as part of a terrorist cell, and they were not actively seeking any other suspects. But they said they had more work to do to determine what motivated him and if anyone helped.

"We have every reason to believe this was an act of terror," New York Mayor Bill de Blasio said.

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Law enforcement officials said they believed Rahami was responsible for the bombing in New York's Chelsea neighbourhood on Sunday NZT that wounded 29 and for the blast earlier that day along a scheduled race route in Seaside Park, New Jersey. No one was hurt in that incident, as racers had yet to pass the site.

Initially, officials said the disturbances had no obvious connections, and they shied from calling either one terrorism. The bombs used were somewhat different. In Chelsea, federal officials said, the perpetrator used two pressure cookers filled with shrapnel and ball bearings - one exploded, and one did not. In Seaside Park, pipe bombs were deployed.

But as investigators reviewed surveillance footage and analysed the bombs, they came to believe that the incidents were related.

Congressman Peter King, a member of the House Homeland Security Committee, said that investigators "pulled fingerprints and the cellphone attached to the pressure cooker" and "traced that to another cellphone that he was going to call that from".

They quietly zeroed in on Rahami, a 5-foot-6, 90kg man whose family runs a fried-chicken joint in Elizabeth, New Jersey.

William Sweeney, assistant director in charge of the FBI's New York division, said that Rahami was not previously on the bureau's radar and that investigators were working to determine whether he was radicalised in some way or if there was some other motive.

Two federal officials said a fingerprint from a cellphone that was recovered proved key to identifying him. Officials also said they obtained DNA evidence from the crime scene. Federal law enforcement officials said that Rahami made several trips to Afghanistan and Pakistan over the past five years and that they were trying to determine whether he was radicalised abroad. One official said he was licensed to carry a firearm.

Authorities began to make their move on Rahami on yesterday. Near the Verrazano-Narrows Bridge in Brooklyn, they stopped a vehicle that had been spotted at a location associated with Rahami and took five people into custody, Sweeney said. King said two of those people were relatives of Rahami. The suspect, though, remained on the loose, and authorities believed him to be dangerous.

At a train station not far from the Rahami family's home in Elizabeth, two homeless men found more explosives in a backpack, and in trying to render them safe, authorities inadvertently detonated one. No one was hurt. Federal law enforcement officials said they believe that Rahami was responsible for that incident, too.

The FBI searched the Rahami family's home, above the chicken restaurant, and, for the first time, broadcast the suspect's name and picture publicly.

Today, they caught a break. A businessman spotted someone who he thought was a vagrant sleeping at his doorway in Linden, New Jersey, and called police, said Linden Mayor Derek Armstead. An officer went to wake the man, and Rahami lifted his head.

The officer immediately recognised him from the "be on the lookout" alert that was distributed, Armstead said.

The mayor said that within seconds, Rahami had fired a shot and hit the officer in the abdomen, though the officer was spared more serious injury by a bulletproof vest. The officer, Angel Padilla, returned fire, hitting Rahami in the shoulder and leg, Armstead said. He said another officer suffered a graze wound from a bullet that ricocheted off a car.

Rahami was soon taken into custody. Video and photographs showed him dazed, with an apparent shoulder wound, lying with his head against the pavement and then being loaded into an ambulance. His precise condition was not immediately known. Rahami has not spoken with investigators, a law enforcement official said.

In addition to the attempted-murder charges, Rahami faces two counts related to his possession of a handgun, said acting Union County prosecutor Grace Park.

Rahami, who was shot multiple times, was taken to University Hospital in Newark for surgery, officials said. They did not elaborate on his condition after surgery.

Bail for Rahami was set at US$5.2 million by a state superior court judge.

New York Police Department Chief of Detectives Robert Boyce said officials might soon distribute images of two people who picked up a bag that contained the unexploded device in Chelsea, took it out and then walked away with the bag. But he said that those people were considered "witnesses" and that detectives had "no information that would link them to this at all."

"Once they picked up the bag, they seemed incredulous they had actually picked this up off the street," he said, "and they walked off with it."