The Metropolitan Opera reached tentative agreements early Monday morning with the unions representing its orchestra and chorus after an all-night bargaining session, and called off its threat to lock out workers a little more than a month before the new season is set to open.

The agreements were announced shortly after 6:15 a.m. by Allison Beck, the deputy director of the Federal Mediation and Conciliation Service, after talks lasted long past the deadline of midnight Sunday that the Met had set for reaching a deal or locking out its workers.

“These were difficult and highly complex negotiations, and I wish to commend the parties for their resolve in addressing multiple and complex issues,” Ms. Beck said in a statement. “We are grateful for their commitment to the collective bargaining process and grateful most of all that the Metropolitan Opera, one of the world’s premier cultural institutions, will continue providing outstanding operas for all to enjoy.”

The terms of the agreement were not immediately disclosed.

The federal mediators stepped in late last month to help broker a deal between the Met’s management and two of its biggest unions: Local 802 of the American Federation of Musicians, which represents the orchestra, and the American Guild of Musical Artists, which represents the chorus, singers and stage managers, among others.