WASHINGTON — NFL Commissioner Roger Goodell and union head DeMaurice Smith refuse to reveal anything publicly about where things stand in their labor talks.

Everyone will know something substantive soon enough — less than a week from now, if not sooner.

That’s because the current collective bargaining agreement is set to expire at the end of the day next Thursday, and federal mediation between the sides will resume less than 72 hours before that. After a full week overseeing face-to-face meetings — more than 40 hours spread over seven consecutive days — mediator George Cohen said “very strong differences remain on the all-important core issues that separate the parties.”

He also said: “At bottom, some progress was made.”

Cohen, director of the Federal Mediation and Conciliation Service, did not explain in his written statement Thursday where the progress came or where the differences stand. The biggest sticking point all along has been how to divide about $9 billion in annual revenues, including what cut the 32 team owners should get up front to help cover certain costs, such as stadium construction.

Among the other significant topics in negotiations: a rookie wage scale; the owners’ push to expand the regular season from 16 games to 18 while reducing the preseason by two games; and benefits for retired players.

If there’s no new deal in place a week from now, the union thinks owners will move to lock out players, threatening the 2011 season. And owners think the union will decertify, allowing for an antitrust lawsuit.

The NFL has said, however, that the deadline could be extended.

“If you’re making progress, you can stop the clock,” the league’s lead labor negotiator, Jeff Pash, said three weeks ago. “It’s not a ‘Thelma & Louise’-type situation, where you just go over the cliff.”