A man has been arrested in New York after explosion near to a bus station in Manhattan injured four people.

The suspect was reported to have been strapped with a pipe bomb which detonated close to Port Authority bus terminal near Times Square at about 7.30am local time (12.30pm GMT.)

The explosion took place at 42nd Street and 8th Avenue, New York Police Department (NYPD) said on its main Twitter account.

"One male suspect is in custody," it added. "No injuries other than suspect at this time. Avoid the area. Subways bypassing #PortAuthority and Times Square Stations.

"The A, C and E line are being evacuated at this time. Info is preliminary, more when available."

New York Fire Department said four people had been hurt but none had life-threatening injuries.

Sources told ABC News the arrested man was aged in his 20s and had been badly injured. The suspect was reported to be Bangladeshi.

Police at Port Authority Bus Terminal (AP) (Ap)

White House Press Secretary Sarah Sanders said President Donald Trump "has been briefed on the explosion in New York City".

The New York Mayor's Office said Mayor Bill de Blasio had also been briefed, adding police and fire crews were on the scene.

Francisco Ramirez told CNN he heard two explosions as he was exiting a bus about 7.45am ET. He heard both blasts distinctly even though he was wearing headphones.

"From what I saw it sounded like it came from the subway, but I'm just guessing," he said. "It was two distinct explosions seconds from each other."

"It was scary. It was just a lot of chaos but I didn't see any injuries."

Andre Rodriguez, 62, told the New York Times that he heard an explosion shortly before 7.30am.

He added: "I was going through the turnstile. It sounded like an explosion, and everybody started running."

Alicja Wlodkowski, 51, was eating at a nearby restaurant when the blast went off.

“A woman fell, and nobody even stopped to help her because it was so crazy,” she said. Then it all slowed down. I was standing and watching and scared.”