CNN

WASHINGTON (CNN) - Former Wisconsin Gov. Tommy Thompson will participate in the Iowa Straw Poll in August, he told reporters in a conference call Wednesday.

Thompson acknowledged that he knew many reporters dialed into the call to find out if he was dropping out of the presidential race, after his campaign sent out a media advisory earlier in the day saying he would make a "major announcement about the future of [his] presidential campaign."

"I've done this, and not all of you have picked up on it," he said. "But I know most of you have signed in this afternoon to find out whether or not I was dropping out of the race."

Thompson criticized former New York City Mayor Rudy Giuliani and Arizona Sen. John McCain for planning to skip the straw poll, calling it a "tradition" in American politics. He said even though it is "an expensive exercise, even for campaigns with big war chests," it is important for candidates to compete in the event.

"I believe it is a mistake to skip the straw poll, and I would hope that Mayor Giuliani and Sen. McCain would reconsider their positions," Thompson said.

– CNN Associate Producer Lauren Kornreich