A pipe bomb explosion in New York City's subway system has injured four people, including the suspected attacker, a Bangladeshi immigrant. In response, the White House has again called for immigration reform.
A small bomb went off in a pedestrian tunnel linking two subway stops near New York's Times Square during the morning commute, in what authorities have called an attempted terror attack.
Four people suffered non-life-threatening injuries, including the suspect, who was taken into custody.
"As New Yorkers our lives revolve around the subways," said New York Mayor Bill de Blasio. "When we hear of an attack in the subways it is incredibly unsettling.
"Thank God the perpetrator did not achieve his ultimate goals."
The explosive device, described as a low-tech pipe bomb, malfunctioned and only inflicted modest injuries to the suspect and three other people.
The suspect, 27-year-old Akayed Ullah, was arrested and taken to hospital.
Authorities have said he came to the United States from Bangladesh seven years ago.
Police are trying to determine whether the suspect actually detonated the device or whether it went off prematurely.
For now, the mayor said, officials believe that the suspect acted alone and police are not searching for any additional suspects.
"There are also no credible threats against New York at this time," de Blasio said.
The explosion, captured on closed-circuit television, happened at around 7:20 a.m. local time (12:20 GMT/UTC) in an underground passageway that connects the New York Port Authority Bus Terminal with the city's vast and sprawling subway system.
The Port Authority is a major transit hub that transports nearly 250,000 commuters between New York City and New Jersey every day.
One of those commuters, Diego Fernandez, was in the Port Authority at the time of the blast. "There was a stampede up the stairs to get out. Everybody was scared and running and shouting," he told the Reuters news agency.
Authorities closed off roads around midtown and the Port Authority was shut down shortly after the explosion, with all subway lines passing beneath the bus terminal ordered to bypass the area.
Trump: US 'must fix lax immigration system'
On Monday afternoon, the White House used the attack to push the need for immigration reform.
The attacker came to the United States from Bangladesh on a preferential visa for family members of US residents or permanent residents.
"First and foremost, as I have been saying since I first announced my candidacy for president, America must fix its lax immigration system, which allows far too many dangerous, inadequately vetted people to access our country," President Donald Trump said in a statement.
He said that the "extended-family chain migration" visa the suspect used to enter the US should be ended.
Monday's explosion came less than two months after an Uzbek man killed eight people when he drove a rental truck down a New York City bike path. The "Islamic State" (IS) jihadi group later claimed responsibility for the attack.
bik, dm, cw/cmk (AP, AFP, Reuters, dpa)