Actor and former Republican Sen. Fred Thompson said Sunday he is considering a run for president in the 2008 election.

"I'm giving some thought to it," Thompson, 64, said on the "Fox News Sunday," program. "I'm concerned about what's going on in this country, in the world."

If he decides to seek the Republican presidential nomination, Thompson would join at least nine other candidates who already have announced their intentions to run or have formed exploratory committees. Former New York Mayor Rudolph Giuliani, Sen. John McCain of Arizona and former Massachusetts Gov. Mitt Romney are the leading contenders a little less than a year before the first primary.

A decision to run is "not really a reflection on the current field at all," Thompson said. "I'm going to wait and see how it pans out, see how they do, how it develops."