US TV's two top late-night talk shows have become the first casualties of the writers' strike which is threatening to bring Hollywood to a halt.
Picket lines have formed outside New York and Los Angeles studios
The Late Show with David Letterman and The Tonight Show with Jay Leno both aired re-runs after their scriptwriters walked off the job.
The strike has been prompted by a disagreement over royalty payments.
Top-rated prime-time show Dancing With The Stars aired as usual, but its hosts had to improvise without scripts.
No new negotiations between the Writers Guild of America and the Alliance of Motion Picture and Television Producers have been scheduled after last-minute talks broke down on Sunday.
Writers want higher fees, or "residuals", derived from work released on DVD or online.
The producers' chief negotiator, Nick Counter, said they were "hunkered down for a long one".
"From our standpoint, we made every good faith effort to negotiate a deal, and they went on strike," he said.
"At some point, conversations will take place. But not now."
The writers say the next move is up to the studios.
Heroes' audience "won't be left in the lurch" said its producer
"My hope is that it won't be too long," said writers' negotiator John Bowman, who told Associated Press that the two sides were talking behind the scenes about arranging further meetings.
"We have more reason to get together than not."
While topical series have been affected by the dispute, most studios have stockpiles of movie and TV scripts to see them through into early 2008.
But some producers have said they are not comfortable about working with these finished scripts during a dispute.
Tim Kring, a producer and writer on Heroes, said he had to revise the ending of the show's 11th episode, in case it became the last to air this series.
"Fortunately, we were able to hustle back," he told AP from a picket line.
"The audience won't be left in a lurch."