Addressing a campaign rally in Great Falls, Mont., Obama noted that he has come in for criticism by McCain regarding his "knowledge about Iraq." However, Obama tried to turn the tables on McCain, bringing up a comment the Arizona senator made Thursday when he told reporters the U.S. has "drawn down to pre-surge levels."

"(McCain is) wrong," Obama said. "It's not true and anyone running for commander in chief should know better."

The Obama campaign and others noted U.S. troop strength is 155,000, well over the 130,000 pre-surge level.

A McCain supporter, Sen. Jon Kyl, R-Ariz., told reporters Friday the "surge troops will be home by the end of July" and said McCain's critics were "trying to nitpick the tense of the verb about the surge troops being home," The Politico reported.

"I don't think tens of thousands of American troops amounts to nitpicking," Obama said Friday. "Tell that to the young men and women who are serving bravely and brilliantly under our flag. Tell that to the families who have seen their loved ones fight tour after tour after tour of duty in a war that should have never been authorized and should have never been waged."