ANNAPOLIS -- Maryland delegates gave preliminary approval to an expansion of gambling that would allow a casino in Prince George's County and give casino owners millions of dollars in tax breaks.

As amended by the House, the bill would give casino owners in Baltimore and Anne Arundel County a greater share of slots revenues -- $32 million -- than approved by the state Senate last week to mitigate losses once a competing site in Prince George's opens.

A gambling expansion must be approved by Maryland voters on the November ballot.

Some lawmakers criticized the bill for giving tax cuts to casino owners the same year the General Assembly approved income tax increases for Marylanders earning more than $100,000 a year.

"You're giving [casinos] a tax break, and you're not giving the citizens a tax break. This is troubling," said Del. Susan Aumann, R-Baltimore County. "It would be thoughtful of all of us to consider what we're doing for a privileged, select few at the cost of others."

But supporters of the legislation pointed to the $750 million the state is projected to collect every year for education.

Allowing table games such as blackjack and roulette and adding the state's sixth casino site, to be in Prince George's, are expected to help fuel a nearly $2 billion gambling industry in Maryland by fiscal 2017, according to state budget analysts.

The House was considering more amendments late Tuesday night before voting on the final bill. Senators were standing by to vote on the House amendments and final passage. Senate President Thomas V. Mike Miller Jr. had no objections to the House changes and said senators would stay at the State House as long as needed.

If the bill is approved, the Cordish Cos., a staunch opponent of a Prince George's casino, could keep as much as 51 percent of slots revenues at its Maryland Live! Casino in Anne Arundel County. Casino owners in Baltimore could keep up to 49 percent of slots revenues at their facility.

Those tax breaks cut deeply into the 67 percent of slots revenues the state now collects, but budget estimates show the state would net $174 million for the education trust fund by fiscal 2017 if the full gambling plan were implemented -- $32 million less than the $206 million originally estimated.

Bidders for a Prince George's site, which could be built at National Harbor or Rosecroft Raceway in Fort Washington, could keep as much as 38 percent of slots revenues.

Delegates also approved an amendment to allow instant ticket lottery machines at veterans organizations throughout Maryland. Ninety percent of the money put into the machines would be paid back to players, while 10 percent would be split between the veterans organizations and the state.