The executive committee of the National Football League Players Association voted unanimously today to call the first regular-season strike in the history of the professional sport.

The strike, affecting 1,500 players, began at the conclusion of tonight's nationally televised game between the New York Giants and the Green Bay Packers.

"I take no pleasure whatsoever in this announcement," NFLPA President Gene Upshaw of the Los Angeles Raiders told a packed news conference following a two-hour meeting of the committee.

"We have been left no choice but to use the only weapon we have left to use to bring management to the bargaining table.

"All NFL training facilities will be struck. There will be no practices, no games, until the National Football League bargains in good faith to reach an agreement."

The first word of players not honoring the strike came from the Los Angeles Rams in Anaheim, Calif., where tight end Mike Barber, a seven-year NFL veteran, and reserve guard Bill Bain, an eight-year pro, said they will continue to play. The Associated Press reported that several other Rams were uncertain whether they would walk out.

"No player in the league wants a strike," said Redskins safety Mark Murphy, a member of the executive committee. "But it has become very obvious by management's refusal to bargain that they have not taken the players' union seriously. They have greatly underestimated the union's strength."

The NFL Management Council, the negotiating arm for the league, met here tonight and after the meeting spokesman Jack Donlan said: "The owners expressed the sentiment that they want to reach a settlement but can't until the players give up their demand for a minimum-wage scale." He said the owners said they were prepared to "go as long as necessary, including the entire season, to prove their point."

There was no indication that meeting what the league would do about games not played during the strike. The Redskins, 2-0 this season, were to play the St. Louis Cardinals at RFK Stadium Sunday afternoon.

Donlan said that if Thursday's scheduled Kansas City-Atlanta game was not played, "We'd be shut down this weekend."

In a prepared statement issued shortly after the strike vote was announced, the management council said, "We regret the union has chosen this path. The only differences between us are the length of the new contract and whether the players will be paid through individual negotiations or by means of a wage scale . . . After we have informed member clubs of our decision, we will explain our situation to the public."

Today's strike vote, widely expected after the collapse of contract negotiations between the union and the management council last week, followed seven months of futile negotiations that began last February in Miami.

Union leaders contended they had made a major concession last Friday. They had offered to drop their demand that the NFL divert 55 percent of its gross income to the players, in exchange asking that the players receive 50 percent of the NFL's $2.1 billion television contract over the next five years plus substantial supplementary payments.

But Donlan, head of the management council, turned down the offer, saying, in effect, that it was still basically a demand for percentage of gross. Donlan also said the NFL rejects the union's demand that players be paid from a trust fund, on a seniority-based scale with performance incentive bonuses.

Ed Garvey, the NFLPA's executive director, said he has filed an unfair labor practice charge with the National Labor Relations Board because of Donlan's insistence that player contracts be negotiated individually.

"He's asking us to waive our right to negotiate salaries. No union can live with that," said Garvey, who said he has no plans to contact the management council to resume negotiations.

Tuesday's strike will be the first regular-season walkout in the six decades of the NFL but the second in two years in a major U.S. professional sports league. Last summer, major league baseball players struck for seven weeks.

Asked how long he expects this strike to last, Upshaw said, "As long as it takes to get a good contract."

According to the Los Angeles Times, the league will lose about $42 million a week during the strike and that each canceled game will cost the players approximately $500,000 in lost wages.

The possibility that the NFL might try to play games using free agents and players who defy the union was given short shrift by the player representatives here today.

"That's an idle threat," said Murphy. "I think that management is smart enough to realize that it doesn't want to risk the threat of compromising the integrity of the regular season."

Donlan has said, however, that playing despite a strike remains one option under consideration, and that the executive committee of the management council will decide on it after weighing recommendations from the NFL's competition committee.

Today's strike vote, authorized by a vote of the full board of player representatives from the NFL's 28 teams at an Aug. 30 meeting in Chicago, was taken with only six of the nine members of the executive committee present.

Dan Jiggetts of the Chicago Bears, James Lofton of the Green Bay Packers and John Bunting of the Philadelphia Eagles were not at the meeting but were polled by telephone.

The other members of the committee, Murphy, Upshaw, Jeff Van Note of the Atlanta Falcons, Stan White of the Detroit Lions, Elvin Bethea of the Houston Oilers and Tom Condon of the Kansas City Chiefs, participated in the decision, and at a news conference took turns berating Donlan for the lack of progress at the bargaining table.

"Jack Donlan says they have a $1.6 billion offer on the table," said White. "We can't find it. We believe he's lying. This is a Jack Donlan strike. When you're backed into a corner you have to fight."

Donlan, who contends the players are provoking the strike, has described management's last offer, made Sept. 8, as costing $1.6 billion over five years. That was based on the expectation that individually negotiated salaries would increase at the rate of 15 percent a year. The offer also included a bonus of $10,000 a year for each year a player has been in the league, to a maximum of $60,000. But there was a provision for a 25 percent reduction in this bonus for every game missed because of a strike.

Asked if the union plans to set up picket lines at games this weekend, Upshaw said, "There won't be any games."

In Washington tonight, Garvey said he doubted there would be league-wide picketing. "Maybe here and there," Garvey said. "Generally, there's nothing to picket. The players won't play."

The three television networks carrying NFL games were scrambling to fill air time if this week's games are not played. ABC said it will run a movie, "The Cheap Detective," in place of Thursday night's game. NBC announced it will air Canadian Football League games for the duration, starting with a doubleheader Sunday. CBS said it will show a replay of the 1982 Super Bowl and extend its NFL Today show to one hour.

In San Diego, radio station KFMB announced it would use its imagination -- literally. It will would broadcast a fantasy football game from San Diego-Jack Murphy Stadium Sunday if the Chargers and Los Angeles Raiders do not play as scheduled.