The "Terminator" actor and former California governor was stopped for a routine check on arrival Wednesday and questioned for 2½ hours before being allowed to leave, an airport customs spokesperson told NBC News.

A source close to Schwarzenegger said that the actor, 76, was detained over a luxury watch he had brought into the country while en route to a charity event in Austria, his birth country. The watch was intended to be a prize at a charity auction Thursday in aid of the Schwarzenegger Climate Initiative, the source said.

“He cooperated at every step even though it was an incompetent shakedown, a total comedy of errors that would make a very funny cop movie,” the source said.

“Criminal tax proceedings have been initiated by us. This will then be processed by our criminal and fines office. It’s too early to say what the outcome will be. There are many factors that have to be taken into account. It will still take some time,” said Thomas Meister, spokesman for Munich's customs office, speaking to German broadcaster RTL.

Meister explained that Schwarzenegger was asked to provide personal, financial information and had the opportunity to consult a lawyer.

"That all takes a certain amount of time. Once that's done, he can leave the customs office," he said. There has been no confirmation of what the next steps in the case might be.

The source close to Schwarzenegger said he agreed to prepay any taxes on the expensive item, but couldn't find a working credit card machine. Officers then walked him to an ATM at the airport to withdraw cash — but the withdrawal limit was too low and the bank was closed, the source said. A second credit card machine worked and the tax was paid.

"The watch will likely still be auctioned tomorrow, and the Schwarzenegger Climate Initiative will properly report it, as all of Arnold’s nonprofits do," the source said Wednesday.

Schwarzenegger was due to host a dinner and charity auction Thursday night in the Austrian ski resort of Kitzbühel, part of a weekend of activities to mark an annual Alpine skiing competition. A news release from his foundation said that among the prizes is a training session with Schwarzenegger.

The proceeds will go toward environmental projects and the annual Austrian World Summit climate conference in Vienna, organized by the Schwarzenegger Climate Initiative.

"'Whenever people say to me, ‘You are the perfect description of a self-made man,' I thank them, but tell them they can call me anything they want — but not self-made. I got a lot of help throughout my life and we all need help," Schwarzenegger said in the news release.

He continued: "So tonight we ask for help. We have to give back and change the world. Today we can all give back by helping to create a cleaner and healthier future."

Andy Eckardt reported from Mainz, Patrick Smith from London and Diana Dasrath from Los Angeles.