Sheldon Adelson, the boss of the Las Vegas Sands, which is involved with investigation and legal issues in the United States and Macau, is now fueling opposition to his plans to build a casino and leisure resort in Madrid or Barcelona.
On Wednesday, a Catalan environmental party, ICV-EUiA, called on Mr. Adelson to appear before the Catalonian Parliament to explain why some of his company’s activities in Macau have run into legal problems in the United States.
Mr. Adelson and the company, is being investigated by the U.S. authorities on suspicion of violating anti-bribery laws linked to its expansion in Macau, the Chinese gambling capital and a major source of income for the Sands.
The company has denied wrongdoing and has said the investigation stems from the accusations of a disgruntled former employee.
The Chinese authorities have also been investigating some of the company’s activities.
In the United States, Mr. Adelson’s preference for working below the radar has been tested this year as he has emerged as the largest donor to the Republican Party in the presidential campaign, in which he has pledged to spend up to $100 million to defeat President Barack Obama.
This week, just days after the presumptive Republican nominee, Mitt Romney, named him as his running mate, Representative Paul D. Ryan traveled to Las Vegas to meet Mr. Adelson for what an aide to Mr. Romney called “a finance event.”
In recent months, plans by Las Vegas Sands to build a giant casino complex in Spain have created a bidding battle between the two biggest cities in the country.
Officials are eager to attract development while Spain is in the midst of its second recession in three years, with record unemployment of almost 25 percent.
The government is struggling to convince investors that the country will not sink deeper into crisis and require a full European bailout.
Mr. Adelson and other Sands executives have made several visits to possible building sites in Madrid and Barcelona.
The two cities also recently sent delegations to Las Vegas in a bid to win over company executives.
The Sands wants the complex, which it plans to call EuroVegas, to have 12 hotels with a total of 36,000 rooms, six casinos with 18,000 slot machines and three golf courses.
Esperanza Aguirre, the head of Madrid’s regional government, has urged the national government to meet concessions requested by Mr. Adelson, including some tax exemptions, as well as an easing of Spanish restrictions on smoking in public spaces.
Ms. Aguirre’s request, however, has led to questions over whether granting special treatment to the Sands would open the door to similar concessions for other investors.
While a final decision was initially expected before the summer, the Sands has pushed back any announcement until September.
The Sands still hopes to start construction in mid-2013 and complete the complex within 10 years.