Hollywood is going to all-out war, after last-minute talks gave false hope that today’s strike by the Writers Guild of America could be averted — or at least delayed for a few days.

Talks collapsed at 9:30 p.m. PST Sunday after more than 10 hours of last-ditch negotiations, only a few hours before the official start of the strike by the WGA at 12:01 am PST.

At that point, the WGA East had already gone on strike in New York just after midnight local time — even though negotiators for writers and companies were still talking in Los Angeles.

“When we asked if they would ‘stop the clock’ for the purpose of delaying the strike to allow negotiations to continue, they refused,” said AMPTP president Nick Counter. “We made an attempt at meeting them in a number of their key areas including Internet streaming and jurisdiction in New Media. Ultimately, the guild was unwilling to compromise on most of their major demands. It is unfortunate that they choose to take this irresponsible action.”

No new talks were scheduled. And the abrupt ending to Sunday’s talks — which had sparked a small wave of optimism that a strike might be averted — may deepen resentment against the WGA.

For its part, the WGA announced after negotiations cratered that it had withdrawn its proposal to double DVD residuals during the session. Counter had insisted last week that the DVD demand was a stumbling block to making a deal.

Additionally, the WGA said, the AMPTP still insisted on no jurisdiction for most of new media writing; no economic proposal for the part of new media writing that would be covered; Internet downloads at the DVD rate; no residual for streaming video of theatrical product; and a “promotional” proposal that allows re-use of movies and TV shows on any platform with no residual; and a “window” of free reuse on the Internet.

“The AMPTP made no response to any of the other proposals that the WGA has made since July,” the WGA added. “The AMPTP proposed that today’s meeting be “off the record,” meaning no press statements, but they have reneged on that.”

Picketing will start at 9 a.m. today more than a dozen high-profile locations in Hollywood with guild members told that they’re expecting to spend at least 20 hours a week on picket lines. Targets include CBS Radford, CBS Television City, Culver Studios, Disney, Fox, Hollywood Center, NBC, Prospect, Paramount, Raleigh, Sony, Sunset Gower, Universal and Warner Bros.

A flurry of back-channel efforts to stave off the strike culminated in the Sunday meeting in Los Angeles that began at 11 a.m. Federal mediator Juan Carlos Gonzalez, who joined the talks a week ago, summoned both sides to the Sunday meeting in the wake of the WGA officially declaring the start of the strike.

Several CEOs were believed to be pushing to jump-start the bargaining process — CBS topper Les Moonves, Disney’s Robert Iger, Fox’s Peter Chernin and Warner Bros. Barry Meyer — but none were among the 25 or so attendees at Sunday’s session.

The strike heightens the likelihood that the AMPTP will turn quickly to launch negotiations with the Directors Guild of America, which has a June 30 contract expiration. Should the DGA make a deal in the next few weeks, it would likely be trumpeted by studios and nets as a repudiation of the WGA’s contention that the companies are not willing to engage in serious bargaining on tough issues.

Labor experts have warned that once the WGA goes on strike, a resolution is not likely to emerge any time soon — particularly with the DGA and AMPTP expected to start negotiations later this month.

“The parties are so far apart on core economic issues that it’s probably not going to resolved quickly,” said Anthony Haller, a partner at the law firm Blank Rome. “The core issues in this dispute aren’t the kind that can be subject to the usual sort of horse-trading you see in typical labor negotiations. It looks like the WGA does not think that the DGA will be strong enough to get what the writers believe they need.”

Until about a month ago, the WGA had been widely expected to not reach a deal by Oct. 31 and then work under an expired contract while the DGA negotiated a deal before the end of the year. But WGA leaders became convinced that such a strategy wouldn’t get the WGA what it wanted and decided instead to threaten to walk out as soon as the guild contract expired.

WGA negotiating committee chief John Bowman has acknowledged the rumors of a WGA strike raised the likelihood that the Directors Guild of America will make a deal soon with the AMPTP. He said that even if the DGA did come to a deal with AMPTP on Internet issues, the writers will not back down.

“The DGA can’t make this deal for us,” he added. “We won’t accept a bad deal.”

Sunday’s last-ditch effort focused on those viewed as voices of moderation, such as “ER” showrunner and former WGA president John Wells, along with WGA negotiating committee members who are also high-profile showrunners such as Marc Cherry (“Desperate Housewives”), Neal Baer (“Law & Order: SVU) and Carlton Cuse (“Lost”).

Conversations among key players from both sides focused on exploring possible concessions in hopes of luring the WGA back to the bargaining table and away from picket lines.

The strike caps a frustrating period for moderates in Hollywood, who were often struck by the unprecedented levels of hostility in three months of negotiations. The two sides were so far apart on so many issues that key players on both sides were seeking not to craft an entire deal but to simply delay the strike for a few days in order to give negotiations another chance.

The major focus of the latest initiative appeared to be to get talks moving without the relentless saber-rattling that’s dominated for the past year with both sides having descended into a bitter battle of words with little actual back-and-forth bargaining. Counter and WGA West president Patric Verrone have repeatedly taken potshots at each other — prompting worries that the relationship between the two men is so damaged that it’s become much more difficult to start moving toward a resolution.

Most of the prior negotiating sessions have ended with both sides issuing vituperative comments. Often, the question of when the next meeting would take place was left unresolved.

Prospects for success out of Sunday’s session had been mixed at best, given the rocky history of this set of negotiations. Additionally, the WGA was already in strike mode over the weekend — featuring a Saturday meeting of 300 strike captains at WGA West headquarters.

Though top execs such as Moonves and Meyer participated in the AMPTP’s pre-negotiations presentation to the news media in July, day-to-day negotiations were handled by Counter, AMPTP VP Carol Lombardini and the top labor relations execs from studios and nets. As a result, the AMPTP spent the first three months of negotiations with a revolutionary residuals revamp proposal that was widely derided by the WGA, leading to a 90% strike authorization.

By the time the AMPTP pulled the residuals revamp off the table on Oct. 16, relations between the two sides had soured enough to diminish the prospects of making a deal.

When the WGA took nine of its 26 proposals off the table two weeks later, Counter responded by saying that negotiations could not continue unless the WGA backed off on its proposals for increased residuals in DVD and Internet downloads.

For studios and networks, the key area for bending would most likely take place in new-media residuals and new-media jurisdiction. The WGA is seeking 2.5% in new-media residuals and TV minimums for work in made-for-new media; the Alliance of Motion Picture & Television Producers is asking for the status quo.

WGA West president Patric Verrone emailed members Sunday, urging them to hit the picket lines.

“Pickets will be the most visible and effective part of the strike in the next few weeks,” he said. “They make us visible in a way that is outside the AMPTP’s control. They deter and often prevent scabs from taking our jobs. They disrupt production, especially when members of other unions honor our line. But most importantly, a large turnout of pickets demonstrates visibly and irrefutably to the AMPTP that we are serious about getting a substantive, fair deal.”

Verrone also warned that participation is mandatory and asked each member to contribute 20 hours a week.

“If there is a personal circumstance making strike support duties impossible when requested, members are required to arrange alternate times,” he added. “Adjustments will be made on a case-by-case basis through the individual captains. Flexibility should not, however, be mistaken for optional participation.”

The requirement to picket is certain to create awkward situations on both sides.

One scribe explained that he was incensed after getting a WGA memo informing him that he would be required to picket the studio he works most closely with. The scribe said he’s perturbed at the WGA for putting him in the position of being seen holding a picket sign in the sight of execs who have paid him big money to write projects.

“This is a potential relationship killer, and it’s wrong of the guild to force me to picket the people who’ve done so much for my career,” the writer said.

The picketing instructions also told WGA members to not talk to the press and to not bring hors d’oeuvres. “This is not a posh strike,” one captain said in the message to members.

(Michael Fleming contributed to this report.)