LOS ANGELES, JULY 11 -- The Directors Guild of America called the first strike in its 51-year history today against two major studios and NBC after rejecting a final contract offer from Hollywood producers.

The national board of the 8,500-member guild decided in a closed-door meeting to direct the work action against Columbia Pictures, Warner Bros. and the NBC-TV network beginning at 6 a.m. Tuesday, guild spokesman Chuck Warn said.

"This is a selective strike," he said. "We have said all along that we intended to implement a strike based on what is best for our members. We expect this will be an effective work stoppage that will help us achieve our negotiating goals."

He said guild members who continue working will contribute 5 percent of their salary to a strike fund to support members idled by the walkout.

The strike to halt production of movies and television feature films and series was announced about two hours after the 21-member national board voted unanimously to reject a final contract offer from film and television producers.

"We are now technically at war," DGA President Gil Cates said after the board emerged from its meeting.

"At the same time," he added, "we are prepared to meet any time and any place to continue talking." No new negotiations are scheduled.

NBC is already beset by a walkout by the National Association of Broadcast Employees and Technicians union.

Jay Rodriguez, a NBC spokesman, said the network has "management people prepared to assume {the directors'} positions."

The start of the directors' strike on Tuesday coincides with NBC's plans to broadcast the All-Star baseball game from Oakland, Rodriguez said.

The strike will also affect network news and sports shows, local news broadcasts, network game shows and the soap operas "Days of Our Lives" and "Santa Barbara," he said.

If the strike lasts longer than a month, he said, it will disrupt filming for the new fall TV season.

"The issues {dividing the two sides} remain the same: whether companies which are making more than ever before . . . can ask working men and women to cut back on their residuals," payments for repeated showings of programs on cable television or those sold into network syndication, Cates said.