NEWARK, N.J. (AP) -- New Jersey Transit train engineers have rejected a labor agreement with management, raising the potential for a strike or a lockout next month.

The Brotherhood of Locomotive Engineers and Trainmen on Tuesday rejected the March deal by a margin of 87%, the union said in a statement. The Railway Labor Act permits the workers to strike or NJ Transit's management to lock workers out as soon as May 15, according to the union.

"Our members are angry," said union General Chairman Tom Haas. "I, along with other NJ Transit engineers, have kept the trains moving but we have gone without a raise since 2019, during a period of high inflation and throughout the pandemic that claimed some of our coworkers."

NJ Transit President and CEO Kris Kolluri said in a statement he was disappointed the agreement was not ratified by members and that he was committed to returning to the bargaining table.

"My focus remains on reaching a fair and sustainable agreement that works for everyone and ensures NJ TRANSIT can continue to provide the reliable service our customers count on," Kolluri said.

A message seeking comment with Democratic Gov. Phil Murphy, whose administration oversees the agency, was also left Wednesday.

Details about the agreement were murky. A statement released at the time of the agreement cited a "reasonable wage increase" for the union's members, a well as the resolution of a long-standing grievance.

Kolluri started in January as NJ Transit's top executive. Last summer, then-President Joe Biden signed an executive order creating a board to resolve the dispute. At the time, NJ Transit said a strike could be possible as soon as March 2025.

New Jersey Transit operates buses and rail in the state, providing an estimated 925,000 weekday trips. The labor dispute goes back to 2019, when the engineers' contract expired.