Talks between The Boston Globe and its unions to prevent the well-known US newspaper from shutting shop continue to hang fire despite a marathon brainstorming session on Sunday night that ran well into Monday morning. While no official word was available, it is likely that the discussions will continue.

Parent company The New York Times has reportedly ratcheted up the pressure on unions, threatening to close the paper within weeks if they do not deliver big cost cuts. The NYT has said it will file a notice with the US government on Monday to shut down the paper if it cannot get millions of dollars in concessions from its unions.

It had set a Sunday midnight deadline for four unions to enable $20 million in cost cuts at the Globe. Earlier it had set Friday as the deadline, but extended it after reporting Saturday that it had made progress.

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

The 137-year-old Globe is the seventeenth-largest newspaper in the United States by daily paid circulation, according to the US Audit Bureau of Circulation. On Sundays, it ranked thirteenth.

The Times has threatened to file a notice under the workers readjustment and retraining notification act, which requires 60 days advance notice before closing a business. This is the hardest pressure that the NYT has so far applied on the unions.

"Filing the WARN notice is a difficult step that we would like to avoid," said a statement issued by the Globe early on Monday. "But unfortunately, given the state of the negotiations, it is one we must be prepared to take."

The Globe was till recent years one of the top US papers. It boasted a strong international, national and local reporting staff that rivalled its bigger competitors like The Washington Post, The Wall Street Journal, USA Today and The New York Times. However, like all US newspapers, it has been forced to cut back on operations as advertising declines.

Snarled negotiations

The Boston Newspaper Guild, the Globe's biggest union, claimed on Sunday evening that it had proposed cuts that exceed the $10 million that the Times has demanded. "This proposal was the product of arduous deliberations," a guild statement said, calling its offers "tremendous sacrifices." It declined to make details available until its members 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 told the leaders of three of the paper's major unions to "enter negotiations or receive a message from the company".

The Times Co said the paper would lose $85 million this year and the cuts were essential to keeping the Globe going, while the guild said it is optimistic that Times 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 deadline extension came after the union said the Times Co made a mathematical error that would result in the union having to make bigger sacrifices.