"We don't comment on matters of extradition, unless and until an individual is on U.S. soil," spokeswoman Laura Sweeney said, citing security concerns.
But the U.S. Marshals confirmed it has been watching Polanski's movements. A provisional arrest warrant was issued after the Marshals and the Los Angeles Police Department learned Polanski would be traveling to Switzerland via Vienna.
Two sources familiar with the case told ABC News that Polanski was arrested after authorities saw advertising on the Internet touting that he was going to attend the film festival in Switzerland. Apparently, the organizers for the event thought it was good for ticket sales and were using his appearance as a marketing tool.
Los Angeles District Attorney's Office spokeswoman Sandi Gibbons told ABC News that this is not the first time Polanski has been in this situation, but he typically hears about a possible arrest ahead of time.
"He hears that he might be arrested if he goes to another country, so he doesn't go," she said, using England as an example.
If and when Polanski is extradited, she said, he will appear in a Los Angeles court. Gibbons said Switzerland is just one of several countries U.S. authorities have worked with to take Polanski into custody.
"We have made requests through diplomatic channels where we've received info that he will be traveling to other countries that have a treaty with the U.S.," she said, calling Polanski a "fugitive." "There has been several times where we have prepared necessary documents with the countries that have treaties with the U.S."
ABC News' Christel Kucharz, Christophe Schpoliansky and DeeAhna Hernandez and Pierre Thomas, and the Associated Press contributed to this story.