New York put on high alert after blast rocks Manhattan

New York City was on high alert yesterday after a powerful explosion rocked Manhattan hours before President Barack Obama and other world leaders were due to arrive in the city for annual meetings at the UN.

Andrew Cuomo, the New York governor, said the blast was an act of terrorism but that the early indications suggested it was not linked to Isis or any other international group.

A second suspicious device was deactivated four blocks away from the Chelsea neighbourhood where the explosion occurred on Saturday evening, and authorities are investigating a potentially broader effort to disrupt the city.

Mr Cuomo said 29 people were hurt in the blast but all of them were discharged from hospital yesterday morning. No one was killed. “A bomb exploding in New York is an act of terrorism,” he said. “As governor, this is one of my worst nightmares.” Whoever was responsible would be brought to justice, he said.

Bill de Blasio, New York’s mayor, said investigators had no information yet on the motivation for the attack, “whether it was political, whether it was personal”, and that no one had claimed responsibility.

Mr Obama, who was expected to arrive in New York yesterday, is among dozens of world leaders who will be in the city this week for the UN General Assembly. James O’Neill, commissioner of the New York Police Department, said about 1,000 extra police and National Guard had been deployed, and officials said random bag checks on public transport would be stepped up.

The Manhattan incident came hours after a pipe bomb exploded close to the route of a road race in Seaside Park, New Jersey. No injuries were reported but the charity run was cancelled.

Given that the device found in Manhattan was built into a pressure cooker, officials said the New York incidents were probably not linked to the New Jersey explosion, although the investigation was still at the early stages.

A terrorist attack in Manhattan could have implications for the presidential election campaign. Isis and the threat of Islamist terrorism have been dominant themes but the risk of domestic terrorism has gone largely undiscussed.

Donald Trump, the Republican candidate, was reported by the Associated Press to have told a rally in Colorado: “I must tell you that just before I got off the plane a bomb went off in New York and nobody knows what’s going on.

“But boy we are living in a time . . . we better get very tough, folks. We better get very, very tough. It’s a terrible thing that’s going on in our world, in our country, and we are going to get tough and smart and vigilant.”

Hillary Clinton, his Democratic rival, said it was important to know the facts before making judgments. “We have to let this investigation unfold,” she said. “I think it’s always wiser to wait until you have information before making conclusions, because we are just in the beginning stages of trying to determine what happened.”

A statement by Isis claiming responsibility for an earlier knife attack in a Minnesota mall added to the sense of jitters. The militant group’s Amaq news agency said a “soldier of the Islamic State” was behind the attack in the Crossroads Centre mall on Saturday, in which a man wearing a private security uniform stabbed eight people before being shot dead by an off-duty police officer.

The New York blast led to heavy traffic congestion in mid and lower Manhattan, and subway trains and buses were diverted. Chelsea is a residential neighbourhood and home to galleries, restaurants and bars.

The explosion, described by one person as “deafening,” happened outside the Associated Blind Housing facility at 135 West 23rd Street. The centre provides housing, training and other services for the blind. The second device was found on West 27th Street.

Rudy Alcide, a bouncer at Vanity Nightclub at 21st Street and 6th Avenue, said that, at first, he thought something large had fallen on to the street. “It was an extremely loud noise. Everything was shaking, the windows were shaking,” he said. “It was extremely loud, almost like thunder but louder.”

Faye Matthias, 19, a tourist from Liverpool, said she heard the noise from her hotel in Times Square. “Everyone is so calm it almost makes it more scary. But when I asked a policeman he said it’s Manhattan, after all. We kind of expect it. I dunno, but if it was in Liverpool we’d all be more freaked out”.

Photos tweeted by the NYPD showed a mangled rubbish skip that had apparently been caught in the explosion. Police told the Associated Press that the blast appeared to have come from a construction toolbox in front of a building.