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A Bangladeshi-origin man was arrested on Monday after a "low-tech" suicide bomb he was was allegedly wearing went off injuring him and three others at the city's transportation hub at the start of the rush hour.
Police Commissioner James O'Neil told reporters that 27-year-old Akayed Ullah had on an "improvised low-tech explosive device attached to his body," which he "intentionally detonated".
Officials said that Ullah was from Bangladesh and had lived in the city for seven years.
Ullah was taken to a hospital and has made statements to police, O'Neil said, but refused to disclose what he had said.
Asked if the suspect had connections to the Islamic State, the Commissioner refused comment saying the investigations were at a preliminary stage.
O'Neil said that that the joint task force of city and federal officials was carrying out a "thorough background investigation" of Ullah who lived in Brooklyn.
He said three other people sustained minor injuries.
John Miller, the head of police counter-terrorism, said that the device was a pipe bomb attached to Ullah's body with velcro.
The bomb went off in a passageway connecting trains in the Times Square underground metro station adjoining the interstate bus terminal in Manhattan, disrupting the morning commute for thousands of people working in the city.
The Port Authority Bus Terminal was evacuated and shut down as scores buses headed to the city from suburbs and other states, but opened after police scoured it for suspicious objects. The Times Square subway station, the city's busiest, was closed for a while.
This is the second terrorist attack on New York in less than two months. A terrorist drove a truck into pedestrians near the World Trade Center on October 31, killing eight people.
New York Governor Andrew Cuomo described Monday's attack as "one of our worst nightmares".
"We are a target," he said, "of those who are against democracy".
New York Mayor Bill De Blasio called it an attempted terrorist attack and added, "Thank God, the perpetrator did not achieve his ultimate goals."
He said that the city was on high alert with stepped up police patrols.
A picture taken moments after the blast showed Ullah on the ground with his clothing ripped showing injuries to his abdomen and arms.