Los Angeles (AP): The Screen Actors Guild will go it alone in contract negotiations with studios after the other major actors union rejected an invitation for joint talks.

In a letter yesterday to SAG, the American Federation of Television and Radio Artists said it would not revisit its decision to sever the guilds' longtime unified negotiations.

SAG's talks with the Alliance of Motion Picture and Television Producers were set to begin today.

The letter from Kim Roberts Hedgpeth, national executive director of AFTRA, was addressed to Doug Allen, her counterpart at SAG. A copy was obtained by The Associated Press.

The guild did not immediately respond to a request for comment.

On Sunday, SAG's national board voted to let AFTRA join its negotiations with producers on a new contract for feature film and prime-time TV. SAG gave AFTRA, whose own talks with producers are set to begin April 28, until tomorrow to respond.

In its letter, AFTRA said it did not appear there has been resolution of the "underlying problems" that prompted its national board to suspend the 27-year-old agreement under which the unions have bargained in tandem.

The AFTRA letter also called the 72-hour deadline set by SAG for a response a "pragmatically impossible timeline."

However, two AFTRA staff members will act as observers at the SAG talks, the letter said, in keeping with the guilds' mutual invitations. AFTRA requested the names of the SAG staffers who will attend its talks.