WASHINGTON (AFP) - Republican John McCain's camp Saturday said Barack Obama's choice of veteran Senator Joseph Biden as his running mate was an admission by the Democrat that he was not ready to serve as president himself. "There has been no harsher critic of Barack Obama's lack of experience than Joe Biden," McCain campaign spokesman Ben Porritt said in a statement. "Biden has denounced Barack Obama's poor foreign policy judgement and has strongly argued in his own words what Americans are quickly realizing " that Barack Obama is not ready to be president." Hammering home the point, McCain's campaign unveiled a television advertisement using Biden's own words to criticize Obama. The ad surfaced before much of the Obama camp had even woken up Saturday, and hours before Obama his VP choice were due to appear together as the Democratic ticket for the first time. The ad shows Biden questioning Obama's lack of experience in a 2007 presidential primaries debate, and saying he would be "honored" to run with or against McCain. The Republican's campaign officials said it will air in several battleground states in the run up to November's general election. It quotes a debate moderator addressing Biden: "You were asked, 'Is he (Obama) ready?' You said, 'I think he can be ready but right now, I don't believe he is. The presidency is not something that lends itself to on-the-job training.'" Biden: "I think that I stand by the statement." The announcer then notes what Biden himself says about McCain. Biden: "I would be honored to run with or against John McCain, because I think the country would be better off." Biden, elected to the Senate more than 30 years ago and who is the current chairman of the Senate Foreign Relations Committee, is widely seen as key to shoring up Obama's national security and foreign policy credentials.