ANNAPOLIS, Md. (AP) — Revenue at a casino in Perryville dropped by about 32 percent in July compared with the same time last year, the Maryland Lottery announced Monday, and the casino has indicated it wants to cut the number of slot machines by about one-third because of increased competition.

The announcement comes as lawmakers are set to convene in a special session on Thursday to consider expanding gambling to include table games like blackjack and a new casino site in Prince George's County. Penn National Gaming Inc., which owns the Perryville casino, has expressed displeasure that National Harbor appears to be the favored spot for a new casino instead of Rosecroft Raceway, a venue it owns in the county.

Bill Hayles, vice president and general manager of the Perryville casino, wrote in a letter to state Sen. Nancy Jacobs that the Perryville casino wants to return 400 to 500 slot machines to the state out of the 1,500 at the facility off of Interstate 95. The state currently owns or leases the machines used by casinos, a practice that could be changed in the special session.

Hayles noted in the letter that revenue projections have fallen far short of estimates made by the state in 2008, when Maryland voters approved a constitutional amendment to expand gambling to allow five locations with slot machines.

"In gross gaming revenue terms, the state estimated that the Perryville site would generate $191 million annually," Hayles wrote. "In reality, we are trending to generate $85 million annually, less than 50 percent off the state's initial gross gaming revenue projections for this facility."

Hayles wrote in a letter dated Friday that Perryville wants to cut back on slot machines due to the impact of the state's largest casino, which opened in June in Anne Arundel County. Hayles also noted that a casino planned for Baltimore, which is scheduled to open in 2014, will further impact the Perryville site. The Perryville casino opened in September 2010 as the first of five casinos allowed under the constitutional amendment.

Hayles wrote that large numbers of unused machines creates an unfavorable perception for customers. He also noted the state can benefit by taking the machines back, because it won't have to buy or lease more for an expansion planned for the Anne Arundel casino.

Increased competition from a casino in Prince George's has generated strong criticism from Cordish Cos., which owns the Anne Arundel casino. Cordish contends a casino near the nation's capital will draw business away from its facility. Cordish also has noted lower-than-expected revenue projections as a reason to at least hold off on approving a sixth casino, pending more data on whether the state's gambling market can support another venue.