The New York Times Company has threatened to close The Boston Globe unless labor unions agree to concessions like pay cuts and the cessation of pension contributions, according to a person briefed on the talks.

The company is looking for $20 million in savings from The Globe, which has already gone through several rounds of deep cost-cutting and staff reductions. The company does not report figures by newspaper, but executives have acknowledged that the Globe lost tens of millions of dollars last year.

The threat to close The Globe was first reported by The Globe on Friday evening on its Web site, Boston.com. The site quoted the leaders of two of the unions describing a meeting Thursday at which the company delivered the ultimatum.

It quoted an unnamed person saying that in the meeting, management said that without the concessions, The Globe would lose $85 million in 2009.