NEW YORK (AFP, REUTERS, NYTIMES) - The Afghan-born US suspect wanted for questioning in connection with both a weekend attack in New York and a New Jersey pipe bombing earlier that day has been taken into custody, according to reports.

New Jersey State Police said Ahmad Khan Rahami, 28, from Elizabeth, New Jersey, was wanted for questioning in connection with both the bombing along the route of a US Marine Corps charity race in Seaside Park on Saturday and the bombing in Manhattan's Chelsea neighbourhood, in which 29 people were injured.

Federal investigators released a mugshot of 28-year-old Ahmad Khan Rahami, who has brown hair, brown eyes and a brown beard, saying he was from Elizabeth, a town adjacent to Newark International Airport.

Rahami, investigators said, was born on Jan 23, 1988, in Afghanistan. His last known address was in Elizabeth, New Jersey.

"Should be considered armed and dangerous," warned the FBI as text message alerts were sent to millions of people in New York, where President Barack Obama and other world leaders were attending the UN General Assembly.

Hours before his name was released, police discovered five pipe bombs near a train station in Elizabeth, detonating one of them overnight as they sought to disarm them. Before dawn, FBI agents conducted a series of raids in the New Jersey city, swarming a residential neighbourhood of low-rise apartment buildings, multiple family homes and small businesses.

The picture that was emerging Monday was that all three incidents - including the discovery of a nest of bombs at the train station in Elizabeth and defused early Monday by the bomb squad - may be connected.

Meanwhile, a CNN report Monday said that United States authorities investigating the blasts in New York and New Jersey said they believe there were indications of a terror cell operating in the two states, CNN quoted law enforcement officials as saying.

CNN said in its report that authorities were seeking "specific people" in response to the discoveries of the bombs.