The first face-to-face talks since January in the Minnesota Orchestra labor dispute ended abruptly Monday after management rejected pay proposals put forward by locked-out musicians.

Management then announced it would cancel two November concerts by the orchestra at Carnegie Hall. Music Director Osmo Vänskä has told the board that scratching the New York concerts would force him to resign.

Vänskä did not return calls on Monday, but he told a Finnish newspaper that his deadline was Monday at midnight.

After Monday’s brief meeting and management’s rejection, the two sides returned to the bitter rhetoric that has characterized the 18-month dispute.

“They have chosen to drive the car that is the Minnesota Orchestra over the cliff,” said musicians’ spokesman Blois Olson.

“We would have negotiated until tomorrow if there had been a substantial reason to do so,” said board chairman Jon Campbell. “After 18 months, we are given an offer in the 11th hour that gives the impression of negotiation.”

Board representatives said neither of the musicians’ two proposals was adequate to address the orchestra’s financial situation.

One proposal by musicians would have cut salaries by 6.7 percent for one year. The other, a three-year offer, would have cut salaries immediately by 8 percent, and then slowly restored the cuts to 2012 levels by the third year.

“We were experiencing $6 million deficits at that level,” said Michael Henson, CEO and president of the orchestra.

Olson said the 8 percent plan would result in $1.1 million in savings. In addition to reduced expenses from having fewer musicians and the departure of several higher-paid players during the lockout, that would bring total musician pay to the 2007 level, he said.

In an offer last Thursday, management sought pay cuts reaching 25 percent by the final year of a three-year deal, plus a bonus of $20,000 per musician. Musicians unanimously rejected that plan on Saturday.

Henson said mediator George Mitchell was not involved in the Monday session, which he described as a presentation, not a negotiation. “We were read an offer,” he said.

Olson said his side had hoped for a counterproposal from management. “They have refused to negotiate,” he said.

Vesa Sirén, who covers classical music for Finland’s largest newspaper, Helsingen Sanomat, and has followed Vänskä’s career for more than 20 years, said he received an e-mail Monday from Vänskä stating that the deadline for his decision was Monday at midnight.

Vänskä’s departure would be significant for many reasons. He is widely credited with turning the orchestra into a world-class ensemble that has won over critics and audiences in Minnesota, New York and Europe. If he were to leave amid an ugly dispute, the orchestra’s reputation would be tarnished. Further, no key leverage points would remain in what already has become the longest lockout in the history of major U.S. orchestras.

Both sides said they hope Vänskä will decide to stay. Clarinetist Tim Zavadil, head of the musicians’ team, said Vänskä has helped the orchestra achieve a golden age. “We don’t want that to end,” he said.

Henson said, “We continue to want Osmo to be here through to the end of his contract in September 2015.”

Olson said the musicians are exploring the possibility of going to Carnegie Hall on their own, and bringing Vänskä with them in November. Asked if musicians had broached the idea with the New York venue, Olson said, “We’ve been in touch. That’s all I can say.”