NEW YORK - NBA labor talks stretched into the wee hours Wednesday morning as players and owners met with a federal mediator, hoping to deliver the progress Commissioner David Stern says is needed to avoid canceling more games.

Both sides met for more than 15 hours, their longest negotiating session since owners locked out players when the old collective bargaining agreement expired June 30.

The talks started about 10 a.m. Tuesday, the 110th day of the lockout.

Stern sought immediate results in just one day of mediation, saying during interviews last week that proposals could get worse and more games could be lost without a deal.

"If there's a breakthrough, it's going to come on Tuesday," he told NBA TV. "And if not, I think that the season is really going to potentially escape from us because we aren't making any progress."

In another interview, Stern told WFAN radio in New York that his "gut" was there wouldn't be NBA games on Christmas if the 110th day of the lockout ended without a deal.

Large gaps remain, with both sides seeking 53 percent of basketball revenues and players opposing owners' attempts to significantly change the salary cap system.

George Cohen, who was appointed director of the Federal Mediation and Conciliation Service in 2009, met with the sides individually at their offices Monday before both brought their full bargaining committees to a hotel Tuesday. The union said it wanted to have the whole week set aside for negotiations, but owners have two days of board meetings beginning today.

Stern wants to be able to bring them a deal. If not, they may have to discuss further cancellations after the first two weeks of the season were already wiped out.

Cohen was present for talks between NFL owners and players for 16 days in February and March before that mediation broke off.

He previously helped broker a deal between Major League Soccer and its players and was lead lawyer for the baseball players' union when it won an injunction against its owners in 1995, ending the 7-month strike.