UPDATE: Police surrounded an apartment in Elizabeth early Monday morning after five explosive devices were found near a train station

ELIZABETH — Service on the Northeast Corridor and the North Jersey Coast Line resumed at 5:30 a.m. Monday morning following an investigation into the discovery of 5 explosive devices near a train trestle in Elizabeth.

NJ Transit's Nancy Snyder warned that delays are likely.

"There was a suspicious package at the Elizabeth train station containing multiple explosive devices," FBI Special Agent Michael Whittaker said.

Elizabeth mayor Chris Bollwage told CNN that two men found a backpack with five devices inside a trash can outside a pub about 500 feet from the tracks around 9:30 p.m. on Sunday.

Whittaker said the FBI and law enforcement are processing evidence and rendering the area safe.

One of the devices exploded when bomb techs from the FBI, Union County and New Jersey State Police tried to disarm it, according to Whittaker, who said there were no injuries in the explosion.

The discovery of the device comes after a pipe bomb went off in a trash can in Seaside Park before a 5K race to benefit a military charity and the explosion of a device inside a dumpster in the Chelsea neighborhood of Manhattan.

Whittaker could not comment on any connection to those two incidents.

Snyder said the devices were not found on NJ Transit property.

Snyder said that bus customers should expect heavy ridership on Monday morning and build in extra travel time due to the suspensions.

Amtrak service was also suspended and the service said trains have been brought into stations to allow passengers to get off if they wish. About 2,400 passengers were on its trains on the Northeast Corridor when service was shut down late Sunday.

NJ Transit and private carrier buses and PATH are cross-honoring NEC and NJCL rail tickets and passes. NJ Transit and private carrier buses and PATH are cross-honoring NEC and NJCL rail tickets and passes.

Whittaker asked anyone with information about the incident to call 1-800-CALL-FBI.

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The Associated Press contributed to this report