JERUSALEM - A Jewish-American billionaire who was questioned by police as part of a corruption investigation into Prime Minister Ehud Olmert on Thursday said he has never given money to the Israeli leader and called suggestions of any wrongdoing "insulting."

S. Daniel Abraham, a philanthropist who made his fortune as founder of Slim-Fast food products, was summoned by police this week to discuss his ties with Olmert. Police suspect Olmert accepted hundreds of thousands of dollars in illegal donations in the U.S., either for campaign financing or possibly as bribes.

"Of course I never gave any money to Ehud Olmert. The very question is insulting to me," Abraham told Israel Army Radio. "This is my reputation at stake and I have no reason to risk it."

Abraham, a strong supporter of Israel who is in the country during its 60th anniversary celebrations, said he believes Olmert is honest and "one of the best prime ministers we have ever had."

The police investigation has cast a cloud over the country's celebrations, raised doubts about Olmert's ability to negotiate a peace deal with the Palestinians and embarrassed the prime minister at a time when he should be enjoying the spotlight.

Another Jewish-American billionaire, Sheldon Adelson, also gave a statement to police this week as part of the investigation. At a Wednesday gala, the casino mogul sat in the front row with U.S. President George W. Bush, first lady Laura Bush and other U.S. and Israeli officials, including Olmert.

The investigation has been focused on the role of Morris Talansky, an American businessman who has said he raised money for Olmert. Talansky, who has denied trying to bribe Olmert and said he believed all contributions were legal, is scheduled to give a court deposition on May 25.

Olmert on Thursday asked the Supreme Court to bar some of Talansky's testimony, a court spokeswoman said.

Police said last week that they suspect Olmert accepted large sums of cash from Talansky. Some of the donations are believed to have taken place during Olmert's 10-year tenure as mayor of Jerusalem as well as while he served as trade minister early this decade. Olmert became prime minister in 2006.

Olmert has denied breaking any laws and promised to resign if indicted.