NEW YORK -- The NBA has canceled the remainder of the preseason and will wipe out the first two weeks of the regular season if there is no labor agreement by Monday.

Commissioner David Stern and deputy commissioner Adam Silver made the announcement after owners and players met for about four hours Tuesday but came no closer to an agreement -- despite a 50-50 split of basketball-related income being discussed as a way to break the stalemate and save the season.

"We were not able to make the progress that we hoped we could make and we were not able to continue the negotiations," Stern said.

No further meetings are scheduled.

"Today was not the day to get this done. We were not able to get close enough to close the gap," union president Derek Fisher said Tuesday, speaking ahead of Stern.

The owners and the players, who have been locked out since July 1, had hoped to make significant progress and save the 2011-12 NBA season. But the two sides could not close the gap between their financial positions, and Stern said regular-season games are now at imminent risk of being lost.

"By Monday, we will have no choice but to cancel the first two weeks of the season," he said.

The players, who received 57 percent of basketball-related income in the last year of the expired agreement, said they made a new proposal of 53 percent of BRI on Tuesday -- a concession which they said would have given owners back more than $1 billion over six years.

According to the players, the owners countered with 47 percent, a slight increase from the 46 percent they had previously offered.

When the owners offered 47 percent, "that pretty much ended (the meeting)," executive director Billy Hunter said.

The two sides, in what Stern called a "very very small group," discussed whether a 50-50 split of basketball-related income was possible -- and that if so, both sides would go back to their constituencies with that plan.

"While we were in the process of doing that ... we were advised by the players that that would not be acceptable to them," Stern said Tuesday. "At that point it didn't seem to make a lot of sense to continue."

In a letter to the union membership Wednesday, Hunter and Fisher explained why they believed the idea of a 50-50 split was not acceptable.

"The overwhelming feeling was that the players are prepared to sacrifice and stand for what we believe is fair. The clear message we have received from the players, and the one we will heed, is not to back down," the letter, obtained by ESPN.com, read. "Yesterday, the owners gave us an opportunity to back down. We refused."

Would the owners have accepted a 50-50 split? "Adam and I felt comfortable and confident we could report to the players we could move to the next subject," Stern said.

"I was shocked (the players) didn't go for 50-50," a source on the owners' side told ESPN The Magazine's Chris Broussard. "That was a gutsy move on the part of the players."

But sources told Broussard that Stern, Silver and San Antonio Spurs owner Peter Holt, in a small-group meeting with Kobe Bryant, Kevin Garnett, Derek Fisher and union lawyer Jeffrey Kessler -- really offered the players 49 percent of BRI, with the understanding that it would actually become 51 percent based on incentives related to the projected growth of the league.

The players countered by asking for 51 percent, which would increase to 53 percent based on those same incentives. The owners rejected that.

After making concessions on basketball revenue, the players entered the last several negotiating sessions looking for the owners to do the same.

Stern said the owners had removed their demand for a hard salary cap, were no longer insisting on salary rollbacks on current salaries, and would have given players the right to opt out of a 10-year agreement after seven years. But the money split was always going to be the biggest hurdle in these negotiations, with owners insistent on the ability to turn a profit after the league said 22 of its 30 teams lost money last season.

The owners indeed wanted to make a deal to save the start of the season, none more than New York Knicks owner James Dolan, sources told Broussard.

Stern said the league is about to take a $200 million hit from missing the preseason. "There's an extraordinary hit coming to the owners and the players," he warned.

"We're long past the point where we're trying to get 100 percent of what we were looking for," Silver added. "We haven't made a secret of the fact that we'd very much like to make a deal."