The union representing U.S. screenwriters called for a strike against film and TV studios starting on Monday in a move giving negotiators one last weekend to reach a contract deal or shatter 20 years of Hollywood labor peace.

The strike deadline was issued on Friday, a day after a three-year contract covering the 12,000-member Writers Guild of America expired. It follows months of talks that deadlocked over the union's demands for a greater share of DVD and Internet revenues.

Each side has accused the other of stonewalling and refusing to budge from unreasonable proposals.

Union negotiators urged a walkout during a boisterous membership meeting on Thursday night, and the Writers Guild's governing board voted to ratify that recommendation.

Hours later, a studio spokesman said the two sides had scheduled a meeting for 10 a.m. Sunday.

Union leaders said at an afternoon news conference there still was time to avoid a strike that, if prolonged, could cost hundreds of millions of dollars in lost revenues and wages.

We have 48 hours and what we really want to do is negotiate, said John Bowman, chairman of the union's negotiating committee. He said that while reluctant to go on strike, the Writers Guild felt it had to act decisively.

We have to inflict as much damage as quickly as possible in order to get this thing over, Bowman said.

The Alliance of Motion Picture and Television Producers, the bargaining arm of the studios, offered a statement by the group's president, Nick Counter, calling the Writers Guild's move toward a strike precipitous and irresponsible.

Our goal continues to be to reach a fair and reasonable agreement that will keep the industry working, he said.

Union officials said that barring a last-minute deal, the strike would begin at 3:01 a.m. EST and picket lines would go up in Los Angeles and New York City.

$1 BILLION AT RISK

The last major Hollywood strike was a Writers Guild walkout in 1988 that lasted 22 weeks, delayed the start of the fall TV season and cost the industry an estimated $500 million.

Los Angeles economist Jack Kyser said a strike of the same duration now could result in at least $1 billion in economic losses.

The union says the overall compensation package sought by writers would cost $220 million over three years, a fraction of the $24.4 billion in revenues generated by U.S. DVD sales and rentals last year alone, according to accounting firm PricewaterhouseCoopers.

A writers' strike would be little noticed by movie and TV audiences at first. Film studios' screenplay pipeline is well-stocked through 2008. And producers of prime-time sitcoms and dramas are said to have stockpiled enough advance episodes to keep their shows on the air until January or February.

But late-night talk shows will go off the air almost immediately since they rely on a daily supply of topical jokes. On his CBS show on Thursday, David Letterman described the producers as cowards, cutthroats and weasels.

Prime-time schedules will start filling up with more reruns and game shows after the networks have burned through fresh episodes. The new shows fighting to hold viewers' attention in the first few weeks of the new season face a grim future if they have to leave the schedule for an extended period.

Negotiations on a new writers' contract began in July and the two sides have remained far apart. They brought in a federal mediator this week to try to break the deadlock on the key issue of compensating writers for the reuse of their work in various digital formats.

The studios have said union demands for higher residuals on DVDs and Internet downloads would stifle growth at a time of rising production costs, tighter profits and piracy. They insist digital distribution of movies and TV remains largely experimental or promotional and new media is just developing.

The union accuses studios of pleading poverty and argues that writers have never had a fair deal on lucrative DVDs. They also see more film and TV migrating toward the Internet and wireless platforms and want a bigger share of that revenue.

(Additional writing by Dean Goodman)