[cnn-photo-caption image= http://i.cdn.turner.com/cnn/2008/images/05/30/art.mccain.email.gi.jpg caption=" A fundraising e-mail sent to McCain supporters Thursday."]
MILWAUKEE, Wisconsin (CNN) - John McCain, the presumptive Republican presidential nominee for president, said he was wrong to use an image of Gen. David Petraeus in fundraising material, and it "will not happen again."
His admission came hours after the Barack Obama campaign criticized an e-mail showing McCain shaking hands with the general who has been commanding U.S forces in Iraq.
It was not the first time McCain had used the picture of himself with Petraeus; it appeared on the candidate's website for several days in April before being taken down.
McCain has been hammering Obama for days over the length of time been since the Democratic front-runner last visited Iraq, mentioning Friday it was "873 days."
"I have visited Iraq on many occasions because I think the most vital decision that any president of the United States can make has got to be about the security of this nation and the lives of the young Americans who are serving," McCain said in an e-mail to supporters sent Thursday afternoon.
Adm. Michael Mullen, the chairman of the Joint Chiefs of Staff, recently took the unusual step of admonishing all members of the military to stay out of politics as the presidential campaign heats up.