Washington, Sep 19 An explosive device inside a suspicious backpack found at Elizabeth train station in US' New Jersey state, exploded on Monday while being examined, media reported.
A loud blast was heard when the bomb squad were investigating the suspicious bag found near the rail tracks on Sunday night, Xinhua news agency reported.
No injuries were reported in the explosion, which went off when a bomb robot was examining it, the reports said.
Elizabeth Mayor Christian Bollwage confirmed that the blast was not a controlled explosion, saying it came when the robot was "cutting into the device."
He said the package appeared to contain several pipe bombs, which "could have hurt a lot of people."
Bollwage said that police received reports from two men who claimed they found a suspicious package with a pipe and wires coming out.
With investigation underway, train service has been suspended between Newark's Liberty Airport and Elizabeth, while New Jersey-bound Amtrak trains from New York are being held at the Penn Station.
The discovery of the package came as the US is on high security alert against terror attacks after 29 persons were wounded in a blast on Saturday in New York City and the explosion of a pipe bomb earlier on Saturday along the route of a Marine charity run in New Jersey.
Nine persons were also injured on Saturday night in a stabbing attack at a mall in the US state of Minnesota.
The incidents are being investigated as potential acts of terrorism.