Developer Milt Peterson stands at the site where he wants to build a high-end casino at National Harbor in Prince George’s County. (Astrid Riecken/For The Washington Post)

Spending by companies with a stake in Maryland’s ballot measure on expanded gambling has now reached $72 million, according to the latest disclosure reports made public Wednesday.

Televisions ads from groups on both sides of Question 7 have continued to escalate in recent days, appearing relentlessly during breaks in news coverage of Hurricane Sandy in both the Washington and Baltimore markets.

With a week remaining until the election, Penn National Gaming, the biggest spender, has now contributed $35.5 million to a ballot-issue committee set up to defeat the expansion plan, which would allow a new Las Vegas-style casino in Prince George’s County, as well as table games, such as blackjack and roulette, at the state’s five previously designated slots sites.

Penn’s properties nationally include a casino in Charles Town, W.Va. that analysts say would take a hit if another large-scale gambling venue opens in Maryland. National Harbor, the 300-acre mini-city on the Potomac River, is considered the most likely expansion site in Prince George’s.

MGM Resorts, the company angling to build a casino at National Harbor, has now given $29.5 million to the ballot-issue committee leading the fight to pass Question 7.

A group led by Caesars Entertainment has contributed $4.6 million to the pro-expansion camp. Caesars plans to open a casino in Baltimore in 2014 that would benefit from table games.

The Peterson Cos., the developer of National Harbor, has contributed $1.7 million to the same ballot-issue committee.

Peterson has also contributed another $700,000 to a separate ballot-issue committee set up by Wayne Curry, a former Prince George’s county executive, that backs the expansion plan.