A device found in a backpack near a train station in New Jersey exploded early Monday while a bomb squad robot was trying to disarm it, authorities said.
Christian Bollwage, the mayor of Elizabeth, said that two men found a bag containing five devices in a trash can at about 8:30 p.m. Sunday. The bag had wires and a pipe protruding from it.
Bollwage said the FBI was attempting to disarm one of the devices when it exploded. It warned that other explosions were expected.
There were no immediate reports of any injuries or damage.
The incident came after 29 people were injured in an explosion in Chelsea, Manhattan, on Saturday. An unexploded pressure-cooker device was also found four blocks away and was being analyzed by the FBI.
Bollwage said the FBI was bringing another robot to remove the four remaining devices found in New Jersey, WUNF News reported. "I don't believe the City of Elizabeth at this stage — was a target," he said, according to WUNF.
NJ Transit services were suspended between Newark Liberty Airport and Elizabeth, and Amtrak trains to New Jersey were being held at New York Penn Station. Amtrak trains heading to New York were held in Trenton early Monday.
Passengers said they were stuck on trains for hours Sunday night. Amtrak said 2,400 passengers were affected.
A pipe bomb exploded in Seaside Park, New Jersey, on Saturday, about an hour from the Elizabeth train station. Officials said the two incidents did not appear to be connected, but they weren’t ruling anything out.
Investigators didn’t immediately say whether they thought the Elizabeth incident was connected to the blast in New York.
FBI agents conducted a traffic stop Sunday just off the Verrazano bridge in connection to the New York explosion. As many as five people were detained after the traffic stop, according to ABC News and The New York Post.
Authorities said Sunday night that surveillance video shows what appears to be the same person moving bombs into place at the site of the New York explosion, and a few blocks north.
New York Mayor Bill de Blasio said Sunday that people will see "a very substantial NYPD presence this week — bigger than ever."
The heightened alert comes as world leaders are gathering Monday for the United Nations General Assembly. President Obama is expected to attend the annual meeting Tuesday, the last of his eight-year tenure.
Contributing: Rick Jervis and Rich Cowen, the Associated Press