A union says a 12-day lockout of hundreds of professors at a New York university has ended.

The Long Island University Faculty Federation, which represents the professors, said Wednesday it reached an agreement with the school that extends their contract to May 31, 2017 to allow more time to bargain.

About 400 members of the school's Brooklyn campus were locked out a few days before classes were scheduled to begin Sept. 7. The contract expired Aug. 31.

The university had said the professors rejected a proposed contract that would cut salaries for new adjunct professors, while offering existing faculty average raises of about 13 percent over five years.

The union also says the school has accepted their proposal to engage a mediator.

Messages left with the university weren't immediately returned.