Sen. Claire McCaskill (D-Mo.) on Thursday said she does not believe that Republican presidential candidate Sen. John McCain (Ariz.) is proud of the ads his campaign has put on the air.

“I don’t think that McCain is proud of the ads he’s running right now,” said McCaskill, a national co-chairwoman of Sen. Barack Obama’s (D-Ill.) presidential campaign,” adding, “I bet John McCain is embarrassed a little bit by some of these ads.”

She added that the spots attacking Obama are “stupid,” “silly” and “juvenile.”

The McCain campaign on Wednesday released an ad comparing Obama’s appeal to that of Paris Hilton and Britney Spears.

“Some Bush-Rove guys have gotten in the back room and hijacked his campaign,” McCaskill asserted on MSNBC. “And they think that they can actually win the White House right now in America by doing nothing but trying to put down Barack Obama? I think they are really underestimating the American people.”

 McCain adviser Nancy Pfotenhauer, responding on the same program for the Arizona senator’s campaign, defended the ads as a humorous attempt to “redirect the conversation to the issues that matter the most to the American people.”