Hollywood screenwriters have gone on strike after talks with studio representatives failed to resolve a dispute over royalties.
Writers want a better deal when their work appears on DVD or online
Pickets were set up outside studios in Los Angeles and New York, after The Writers Guild of America asked its 12,000 members to stop working.
Drivers honked in support as throngs of writers waved placards, said reports.
Late-night TV chat shows are likely to be the first productions to suffer with drama to follow if the strike drags on.
In New York, strikers wielded banners reading "On strike" and "No money, no funny".
Michael Winship, president of the Writers Guild of America East, said: "The seven-word mantra is: 'When you get paid, we get paid.'"
The last strike by screenwriters, in 1988, lasted a crippling 22 weeks.
The BBC's Peter Bowes says the strike is expected to have a ripple effect throughout Los Angeles with businesses that rely on the entertainment industry being hit hard.
He says one estimate puts the potential cost to the city at $1bn.
Negotiators for the WGA and the studio representatives, the Alliance of Motion Picture and Television Producers (AMPTP), held talks on Sunday night with a US federal mediator in Los Angeles.
The writers want higher fees, or "residuals", derived from work released on DVD or online.
"It's about our livelihood," one striking writer told the BBC on a picket line in Los Angeles.
"We rely on residuals, we rely on money from technology, and the internet is a large part of that and it's going to be an even bigger part of that in the future."
But the studios have rejected their demands as unworkable.
Nick Counter, president of the AMPTP, said earlier that no progress was possible "for overriding business reasons".
"The DVD issue is a roadblock to these negotiations," he added.
Talk shows hosted by stars such as Jay Leno, David Letterman and Jon Stewart are expected to stop almost immediately as they rely on a supply of topical jokes.
It was anticipated NBC would broadcast repeats of Leno's programme, The Tonight Show, plus Late Night with Conan O'Brien and Saturday Night Live from Monday if the walkout went ahead, the Hollywood Reporter said.
It also said old episodes of The Daily Show and The Colbert Report would be screened under contingency plans by the Comedy Central channel.
But as yet it was unclear what other networks intended to do, it added.
Leno made a quip about the strike on-air on Friday, saying:
"They call it the toughest time for comedy writing since those three weeks back in the 1990s when Bill Clinton stopped dating. Remember that?"
Filling the gaps
The 1988 action disrupted the autumn television season.
David Letterman had a show affected during the 1988 strike
At that time, Letterman was host of NBC's Late Night, and his programme was taken off-air at first. It did return before the end of the strike, however, but many other shows remained unbroadcast.
It is anticipated daytime TV output, such as chat shows and soap operas, may be next to suffer in the current walkout. These series are typically recorded about a week in advance of transmission.
The strike would not immediately affect production of film or primetime TV programmes, the Associated Press reported.
This was because most movie studios had already kept aside a number of scripts, and many high-profile TV dramas and comedies had enough scripts or completed shows to last until early next year.
But then Hollywood analysts do expect the supply of shows such as Desperate Housewives, Ugly Betty and CSI to fizzle out, and many writers fear the TV networks will turn to additional repeats and reality programmes to fill the resulting gaps.
We asked for your views on this story. Here is a selection of the responses received.
I have screenplays registered with the Writer's Guild of America West, so I can have the additional protection when pushing my work overseas, mainly in Japan as a backdoor, so I can get into the USA. I think the MBA (Minimum Usage Agreement) is a poor man's farce, plus what a writer has to do just to achieve entry into the Guild is nearly beyond belief. But on the other side, the amount of cut-throat dishonesty that exists among leading industry producers is much worse. Without the Guild's protection we really would have nothing. Given the global economy in which all mediums compete with everything, a larger royalty belongs to the writers. And let's not forget the overcost of for-profit health care in America that the Guild provides to writers as a benefit. This is always left out of the equation. It's not a "benefit", when in reality we are fighting for our lives against a for-profit health care system that's against all of us. I fully support all the writers' efforts as one. But as a free agent, I will continue.
Alan Colosi, Boston, Massachusetts
As one of the very few British members of the Writers Guild of America (West), I'm saddened by the Producers' attitude in this negotiation. This is a New Century, and a different world we live in. The Internet has helped change the fabric of our existence, and the WGA Membership are seriously taking new distribution methods for our created material into account now...our livelihoods depend upon it. I believe our Guild have the grim resolve to push this unfortunate strike, until we're finally given a fair piece of the pie we're so instrumental in baking. Be warned, Mr Counter: we're unlikely to cave as readily today as we did nearly two decades ago...
Peter Briggs, Los Angeles, California & London, UK
I have been writing these worthless scripts for years. I am actually pleased there will be a strike. Not necessarily for better royalties. I think it will give people a chance to reflect upon the mind-numbing quality of what we are churning out.
Andrew Johnston, Evreeware, California
This isn't just about the writers, it affects everyone in this town... from the make-up artists to the production assistants just starting out. People think that it's just rich writers being affected, but they are way off. This town thrives on this industry and the fact that the rich execs wont pay a fair rate to those that deserve it blows my mind. The big issue here is that this is just the start. The contracts with the Directors Guild (DGA) and Screen Actors Guild (SAG) will also be facing this same issue in a few months, so they better figure out something... quick!
David Tobin, Hollywood, California
The bright side is that maybe unknown writers like me will be able to get their work noticed out of sheer desperation. Hopefully they will find the talented, unnoticed writers that were unable to get their scripts noticed.
Daniel Tokle, Lakewood, Callifornia
Daniel - on behalf of my fellow members of the WGA, I want to remind you that if you submit materials to the signatory studios and production shops during a strike, your action will effectively ban you from joining the WGA, thereby stopping your prospective writing career before it has even begun.
JK, New York, New York
I applaud David Letterman's description of the producers as "cowards, cutthroats and weasels". But he *was* reading it off the autocue.
I am a British writer who also works in LA and am a member of the WGA. It may seem to people outside the industry that it's one privileged group whingeing at another. Apart from the fact that many, if not most, writers struggle to make a living, what's at stake is an erosion of the fundamental right to be paid fairly for the work you do. To put "fair share" into context: the writer's royalty from a $10 DVD is four cents. The studios have been trying to reduce this!
Mark Burton, Reading, UK
Actually, Mark Burton's number is inaccurate - the writer's royalty from a $10 DVD would be TWO cents. It's FOUR cents on a $20 DVD. Which is less than it costs to wrap the thing in plastic.
Stephen, Los Angeles, California
It's not like the trash collectors are going on strike, which would have a devastating affect on our lives. It's hard to take someone seriously who produces nothing that society needs.
Frank Nelk, Boston, Massachusetts
Writers have always been second-class citizens in Hollywood, viewed as little more than the "help". How pathetic is it that Letterman and Leno make millions per year, but if the writers walk out they have to shut it down? Must be nice to earn that much off the work of others...
JB, Palmetto, Florida
About time we had a clearout of these mind-numbing shows which are endless unoriginal commercials punctuated by a few minutes of dialogue. Only a few are worth preserving but even they get crass after a few episodes. Hope the strike goes on forever, then we might get a rethink of how to entertain!
Bob, Spring, Texas