The first strike by Hollywood writers in nearly 20 years got under way with noisy pickets on both US coasts -- a walkout that threatens to disrupt everything from late-night talk shows to soap operas.
The strike began on Monday after daylong talks on Sunday failed to produce an agreement on payment to writers from shows offered on the Internet.
The Tonight Show, the late night talk show on NBC hosted by Jay Leno, will immediately go into reruns, according to a network official who spoke on condition of anonymity because the person lacked authorization to comment publicly.
KTLA-TV reported that fans of the Ellen talk show, hosted by Ellen DeGeneres, were told at the NBC lot in Burbank that there would be no taping on Monday.
Comedy Central previously said The Daily Show with Jon Stewart and The Colbert Report mock news shows would likely go into repeats as well.
The strike will not immediately affect production of movies or prime-time TV programs. Most studios have stockpiled dozens of movie scripts, and TV shows have enough scripts or completed shows in hand to last until early next year.
At the CBS lot in Studio City, about 40 people hoisted signs and applauded when midmorning picketing began.
Robert Port, a writer for the TV show Numb3rs, said he was as ready as possible for what could be a long walkout.
"We live in Los Angeles, your bank account can never really be ready for this," he said.
Across town at the Paramount Pictures lot on Melrose Avenue, about 50 strikers dressed in jeans, athletic shoes and red strike T-shirts carried signs reading, "Writers Guild of America on Strike."
Drivers honked their horns as they passed the studio's landmark gate.
The first noisy strikers appeared outside the Today show set at Rockefeller Center in New York, where NBC is headquartered. The morning talk and news show is not directly affected by the strike because news writers are part of a different union.
A giant, inflated rat was displayed, as about 40 people shouted: "No contract, no shows!"
"They claim that the new media is still too new to structure a model for compensation," said Jose Arroyo, a writer for Late Night with Conan O'Brien.
"We say give us a percentage so if they make money, we make money," Arroyo said.
The Alliance of Motion Picture and Television Producers (AMPTP) said writers refused a request to "stop the clock" on the planned strike while talks continued.
"It is unfortunate that they choose to take this irresponsible action," the alliance said in a statement.
Producers said writers were not willing to compromise on major issues.
Writers said they withdrew a proposal to increase their share of revenue from the sale of DVDs that had been a stumbling block for producers.
They also said proposals by producers in the area of Internet reuse of TV episodes and films were unacceptable.
"The AMPTP made no response to any of the other proposals that the WGA has made since July," writers said in a statement.