A "minor" train derailment near New York Penn Station halted NJ Transit service Thursday night, according to the transit agency.

NJ Transit said the mishap happened at a "slow speed," around 6:20 p.m.

There were no injuries, according to a New York City fire department spokesman.

The Montclair-Boonton Line train was headed from Penn Station to Montclair State University when the derailment occurred shortly after leaving the station and before the Hudson River tunnel, NJ Transit spokesman Jim Smith said.

#NJTransit says NJT rail tickets and passes will be cross honored by NY Waterway. #njcommute — Larry Higgs (@CommutingLarry) October 5, 2018

One set of wheels on one car, which was closed to passengers at the time, derailed, the spokesman said. There were no injuries to the approximately 900 to 1,000 passengers on the train.

Train service in and out of Penn Station New York is suspended due to a NJ Transit minor slow speed train derailment near Penn station. Midtown Direct Line trains will be diverted to Hoboken Terminal. PATH will cross honor rail tickets and passes at 33rd St., NPS and HOB. — NJ TRANSIT (@NJTRANSIT) October 4, 2018

Amtrak said service was restored later Thursday night, but travelers should expect delays.

"Rail traffic to and from New York Penn Station has resumed, after being temporarily suspended due to a slow-speed commuter train derailment," Amtrak said in a statement.

"Passengers should expect delays throughout the evening as crews work to inspect the infrastructure, make any necessary repairs, and restore all tracks for service," the statement said.

Photos on social media showed large crowds at the station.

New York City Emergency Management said to expect delays on NJ Transit service in and out of Penn Station

TRANSIT ALERT: If you're heading to #PennStation right now, these are the crowds you may face. Expect delays on @NJTRANSIT trains in and out of the station because of a minor train derailment. NJT buses will cross-honor NJ Transit rail tickets and passes. #NY1Commute pic.twitter.com/2juPUrJSmx — Spectrum News NY1 (@NY1) October 4, 2018

"Consider alternate routes and allow for additional travel time," the agency said in an alert.

Noah Cohen may be reached at ncohen@njadvancemedia.com. Follow him on Twitter @noahyc. Find NJ.com on Facebook.