BOSTON (AP) – The Boston Globe reporters and editors who narrowly rejected wage and benefit concessions face greater uncertainty as their union launches potentially costly litigation to stop a steeper pay cut imposed by their employer.

The Globe’s parent company, The New York Times Co., said Tuesday it will keep the 137-year-old newspaper open after achieving the needed $20 million in annual savings.

But Boston Newspaper Guild leaders said they would try to block the 23 percent pay cut that the Times Co. unilaterally imposed to make up half of those savings.

Following a nearly two-hour meeting with union members Tuesday night, Guild president Dan Totten announced that the union was filing an unfair labor complaint with the National Labor Relations Board.

Totten said a meeting with the NLRB is scheduled next Tuesday, and he said the Guild is also calling for “independent and impartial” third party mediation. “The Boston Newspaper Guild has only wanted one thing throughout, and that is fairness,” he said.

Union leaders also plan to discuss the situation Monday with representatives of the Times Co., but Totten would not characterize that meeting as a negotiating session.

Labor and media experts say such a protracted dispute could further damage the Globe or increase the risk of its closure.

The Guild, which represents about 700 editorial, advertising and business employees, voted 277-265 Monday to reject a contract proposal that included an 8.3 percent wage cut, five-day unpaid furloughs, the elimination of 190 lifetime job guarantees and cuts in health care and pension benefits.

It would have replaced terms in an existing contract that runs through the end of the year.

The company had said that if the Guild rejected the contract proposal, which union leaders sent to a vote without recommending approval or rejection, it would declare an impasse in the negotiations and impose the 23 percent pay cut.

The Boston Globe followed through on that threat after the vote late Monday, saying wage cuts would take effect Sunday because the parties were at an impasse.

“I have to do everything within my means to safeguard this institution,” Publisher Steven Ainsley wrote in a letter to Guild employees.

Either set of cuts amounted to $10 million in savings annually, which the Times. Co said it needed, as part of $20 million total from all Globe unions, to stabilize the Globe’s finances and avoid shuttering the newspaper.

Six other unions already have accepted concessions, but they were contingent upon the Guild also approving cuts. One other union did reject cuts, but the Times Co. said its decision did not affect the $20 million in savings needed.

Earlier Tuesday, Totten asked the Times Co. to rescind its declaration of an impasse, saying the company violated contract and legal obligations by doing so.

“The Guild renews its proposal for the parties to engage in mediation prior to any unilateral change,” Totten wrote to Globe Senior Vice President Gregory Thornton.

The Globe reported on its Web site Tuesday that Thornton, in a subsequent letter to Totten, rejected the union’s request to rescind the declaration of an impasse.

A long legal dispute also could increase the chances of the Globe’s closure, despite the Times Co.’s pledge Tuesday not to do so. Although the company would be saving payroll costs before the issue is resolved, it would be liable for any back pay should it lose. And both sides potentially could spend millions of dollars in legal fees.

Fitch Ratings media analyst Mike Simonton said that by the time the issue is resolved, the $20 million in annual savings might not be enough.

“Profitability is a moving target,” he said. “As revenue continues to decline, the amount of cost reductions required continues to increase. Twenty-three percent today may be a higher number in the future.”

Rick Edmonds, a media business analyst at the nonprofit Poynter Institute, said union leaders risk “sinking the ship as they try to fight for a better deal.”

Michael Paulson, a Globe reporter who attended the meeting Tuesday night, said that while there were a “couple of flashes of anger,” the general tone of the meeting was one of apprehension.

Paul Bachand, a print designer who has worked at the newspaper for 28 years, said the mood among the staff was the worst he has ever seen. But he also struck an optimistic tone.

“I know a lot of people are confused and scared, but something is going to get worked out,” he said.