Up to five suspicious devices were found in a backpack in a wastebasket in New Jersey, one of which exploded as bomb experts dealt with it, media and the local mayor said early Monday.

As a robot examined one device it "cut a wire and it exploded," the mayor of the city of Elizabeth, Chris Bollwage, told CNN. No injuries were reported.

Earlier in the evening Bollwage told journalists that two men walking near the train station had seen a package in a waste basket and took it.

After noticing "wires and a pipe," they alerted local police.

A local bomb squad responded to the scene and a drone examination found that "it could be suspicious and it could be a live bomb." FBI and state police were also called to help investigate.

The latest New Jersey investigation is underway amid heightened tensions after a blast in New York's Chelsea neighborhood injured 29 people Saturday, four blocks from the discovery of a second bomb that was defused safely and sent to authorities for examination.

READ: Mystery attacks in New York, New Jersey and Minnesota raise fears of terrorism

Earlier that day a pipe bomb went off in a trash can on the route of a Marine Corps run before it began on Saturday morning in Seaside Park, New Jersey, causing no injuries but forcing the race's cancellation.

It remains unclear whether the suspicious backpack in Elizabeth was connected to any of those events.

Trains traveling through Elizabeth from New Jersey's local transit line and Amtrak had been suspended, the mayor said.