The 30-second ad from the campaign of the Arizona senator ran in Denver Saturday night and was to run Sunday in Washington and Pennsylvania, the Washington news Web site and newspaper Politico reported.

In the spot, an announcer says, "Barack Obama never held a single Senate hearing on Afghanistan. He hadn't been to Iraq in years. He voted against funding our troops. And now, he made time to go to the gym, but canceled a visit with wounded troops. Seems the Pentagon wouldn't allow him to bring cameras."

The reason why Obama, the Illinois senator who is the likely Democratic presidential nominee, canceled the visit is disputed. He claims U.S. military officials barred the visit as political, while the Pentagon claims Obama left when a campaign adviser wasn't allowed to accompany him, Politico said.

Obama spokesman Tommy Vietor said McCain "is an honorable man who is running an increasingly dishonorable campaign."