Negotiators for the National Basketball Association and its players met constructively, they thought, for nearly two hours Thursday morning. Then they broke for lunch, and each side had to wonder what was in the water that the other side had with its food.

Within 15 minutes after the negotiators returned from lunch, the owners' group abruptly ended the bargaining session, leaving both sides accusing the other of deliberately torpedoing the meet-ing and the immediate chance for progress in the off-season lockout.

"They were like my four-year-old," said Karl Malone, who traveled from Alaska for his first taste of collective bargaining. "I don't want to play anymore so I'm going home."

The half dozen owners who were in the conference room of a midtown Manhattan law office, on the other hand, were described as stunned and insulted by post-lunch developments.

"We thought the best thing to do to preserve any semblance of a bargaining balance for continuity would be to end discussions right there," said Commissioner David Stern.

The negotiators were meeting for the first time since June 22, the first time since the league imposed its lockout July 1, suspending all NBA business, including the signing of free agents and the payment of salary teams contractually owe players for the 1998-99 season.

Now no further bargaining sessions are scheduled, though lawyers for the league and the players will meet Friday with an arbitrator, John Feerick, to schedule a hearing on the union's grievance over the teams' failure to pay guaranteed salaries. Fee-rick's decision in that case is expected to have a major impact on the future of talks.

League officials, in fact, suggested that the union strategy centered not on negotiations but on the salary grievance and an unfair labor practice charge it filed with the National Labor Relations Board.

"The strategy here is to litigate, arbitrate and make no concessions," Granik said. Billy Hunter, the union chief, countered by saying the players will use every avenue available to them to undermine the lockout but that they want to negotiate a new agreement.

At the morning session, the owners who were present engaged in dialogue with the 13 players who were at the large table. Stern called the exchange constructive. Hunter said at least part of it was acrimonious, particularly an early exchange between Malone and Jerry Colangelo of the Phoenix Suns.

But the exchange prompted the union to make a post-lunch proposal. "Colangelo," related Jeffrey Kessler, one of the union's outside lawyers, "said we had to address the drug agreement, rookie issues and a hard salary cap. They want to slow the growth of salaries."

So the union returned from lunch with a proposal that would change the 20 percent salary increase veterans receive in new contracts, grant clubs the right-of-first refusal on players ending their three-year rookie contracts and would add marijuana to the drug-testing list if all economic issues were resolved first.

But the owners viewed the over-all effect of the elements of the economic proposal as perilous. The union's ideas, they said, could increase, not decrease, the percentage of revenue that would go to player salaries. In addition, the owners took offense at remarks made by Kessler after they said the proposal wasn't productive.

"When they lecture you on the grave risk you face if you don't take their proposal, that's when it's time to leave," Stern said. "That's not the tone in which we address the players."