LAS VEGAS (AP) - World Series of Poker organizers are preparing for 10,000 entrants to this year's main event, a 14 percent increase from last year, despite a U.S. crackdown on online gambling sites that have boosted the tournament's popularity.

Organizers said Wednesday that the number was for planning purposes only, and did not reflect confidence that last year's 8,773 entrants would be topped. Half of last year's record number of entrants were estimated to have won their seats in online qualifier events.

"It is not either a target, a goal or a prediction," tournament commissioner Jeffrey Pollack said during a conference call with reporters. "But again, you've got to plan for something. We're planning for a top level of 10,000 but if there are more, we will figure it out."

The tournament plans to build a structure beside the host Rio casino-hotel in Las Vegas and increase the number of tables to 258, Pollack said. That would be enough to allow more than 3,000 players to play the first three days of the main event.

A higher number of entrants would mean the grand prize for the world's richest poker game would exceed last year's $12 million.

The tournament also said it was distancing itself from online poker sites that accept bets from U.S. players, in line with the Unlawful Internet Gambling Enforcement Act. The measure was signed by President Bush as part of a port security bill in October.

Groups associated with dot-com poker sites that take U.S. wagers will no longer be allowed to set up VIP booths and displays, Pollack said.

The tournament, owned by Harrah's Entertainment Inc., also is warning sites that improperly use trademarked material, such as the tournament name, to stop.

That could include poker Web sites such as FullTiltPoker.com and Bodog.com, which are holding satellite tournaments that award World Series of Poker seats worth $10,000 apiece.

Pollack said players would not be able to sport logos from sites that continue to violate its trademark rights by the time the first events of the 47-day tournament series begin June 1.

The trademark warnings could crimp registrations, said Internet gambling expert and lawyer Anthony Cabot.

"I think they're in a difficult position," Cabot said. "They're a licensed entity and therefore have to be cognizant of the new laws and the potential impact those new laws could have on them as a company. At the same time, implementation of those policies will have a negative economic impact on the tournament."