With less than two hours to go before a midnight deadline, The Boston Globe and a key union have not agreed on concessions that parent company The New York Times Co says it needs to keep the newspaper alive.

The Times set a Sunday night deadline for four unions to find $20 million in cost cuts at the Globe. It had set Friday as the deadline, but extended it after reporting that it had made progress.

There is no agreement so far, and the deadline remains midnight, a Times spokeswoman said.

If the Globe's management and the unions fail to reach an agreement, one of the most well known and largest U.S. newspapers could close, leaving Boston without a daily, full-service general newspaper of comparable size.

The Boston Newspaper Guild, the Globe's biggest union, said it proposed cuts that exceed the $10 million that the Times has demanded of it.

This proposal was the product of arduous deliberations, the guild statement said, calling its offers tremendous sacrifices. It declined to make details available until its member had a chance to review them.

Negotiations have become tangled over some benefits that the Times wants to erase, including some lifetime job guarantees, the Globe reported on its website on Sunday.

Management has summoned the leaders of three of the paper's major unions to Weymouth, Massachusetts, southeast of Boston, and told them to enter negotiations or receive a message from the company, The Globe quoted union officials as saying in an article on its website Sunday night.

Union officials have said they have met, or are close to providing the financial concessions sought by the Times Co, the Globe reported.

It said negotiations have become tangled by the Times' demands for changes in contract language, such as the elimination of lifetime job guarantees for veteran members in some unions.

The Boston Newspaper Guild has met what the New York Times Company and Globe management said they needed, said a Guild statement released on Sunday morning.

It did not provide specific examples, but said it made recommendations that would entail tremendous sacrifices, including pay and benefit cuts.

The Boston Herald reported that large numbers of layoffs could be on the table. Guild and Times officials declined to comment on the negotiations.

The Guild, pressmen and mailers unions have some members with lifetime job guarantees, the Globe reported.

The Globe is talking with the Boston Newspaper Guild, its largest union, in Weymouth. It wants $10 million in concessions from the guild, with the balance coming from the others.

The Times said the paper would lose $85 million this year and the cuts were essential to keeping the Globe open.

The guild said it is optimistic that the Times Co is genuinely committed to reaching agreement.

The Boston Newspaper Guild is one of the largest of about a dozen unions at the Globe, and represents about 600 people in editorial, advertising and other business roles.

While The Times and the union cited progress, the extension came after the union said the Times Co made a math error that would result in the union having to make bigger sacrifices.

(Reporting by Robert MacMillan; Editing by Maureen Bavdek & Richard Chang)