ANNAPOLIS -- Tax breaks for casino operators were approved by a Maryland House of Delegates committee late Monday evening, as lawmakers advanced gambling legislation that would allow a casino in Prince George's County.

The Ways and Means Committee passed Gov. Martin O'Malley's gambling expansion bill 13-7 after hours of debate behind closed doors and in committee over amendments to the bill.

The full House is expected to resume debate on the gambling bill Tuesday afternoon.

If passed, the bill would authorize a 3,000-slot casino in Prince George's, which could be located at National Harbor or Rosecroft Raceway in Fort Washington.

Table games such as blackjack and roulette would also be legalized at all existing casino sites.

Included in the measure is an increase in the share of revenue for casino operators in Anne Arundel County and Baltimore.

Operators at each site could keep up to 10 percent more of slots revenues -- in addition to the 33 percent they now collect -- depending on the impact a Prince George's casino has on their profits.

Anne Arundel will automatically receive an 8 percent boost in its share when a Prince George's casino opens; Baltimore will gain a 7 percent bump. And operators can appeal to a new gambling commission for as much as a 10 percent total boost in their share of slots revenues.

The House amendments grant larger guaranteed shares of slots revenues than the companion legislation passed by the Senate last week.

The extra revenue gained by those shares must be spent on advertising, marketing or capitol improvements intended to keep the casinos competitive in what some lawmakers fear could become an oversaturated gambling market in Maryland.

"We need for all of these guys to be financially sound," said Del. Frank Turner, D-Howard. "I don't want these operators to fail, because if they fail, we fail as a state."

All measures in the gambling legislation must be approved by voters statewide on ballots in November.

As amended by the House committee, casinos in Anne Arundel and Baltimore would also gain a greater share of slots revenue to cover expenses for owning and leasing slot machines at their sites. The state, which now owns and leases all the slot machines to the casinos, could save up to $150 million annually, according to state analysts.

Baltimore would keep an extra 6 percent. Anne Arundel will keep 8 percent more.

Despite giving casino operators a greater share of slots revenues, lawmakers estimate the state will earn an additional $200 million annually by expanding gambling options in Maryland.

"The net effect in the education trust fund is a positive, not a negative," said Del. Eric Luedtke, D-Montgomery.