John Podesta, Hillary Clinton's former campaign manager, slammed Donald Trump for a morning tweet about him and called the president a "whack job."

Podesta's comments follow an early morning tweet by Trump, who is in Germany for the G-20 summit:

Everyone here is talking about why John Podesta refused to give the DNC server to the FBI and the CIA. Disgraceful! — Donald J. Trump (@realDonaldTrump) July 7, 2017

1/ On a x-country road trip with my wife; — John Podesta (@johnpodesta) July 7, 2017

2/ Pulled in for a pit stop in E. Fairmont W. Va. to see that our whack job POTUS @realDonaldTrump is tweeting about me at the G20. — John Podesta (@johnpodesta) July 7, 2017

3/ Get a grip man, the Russians committed a crime when they stole my emails to help get you elected President. — John Podesta (@johnpodesta) July 7, 2017

4/ Maybe you might try to find a way to mention that to President Putin. — John Podesta (@johnpodesta) July 7, 2017

5/ BTW, I had nothing to do with the DNC. — John Podesta (@johnpodesta) July 7, 2017

6/ God only knows what you'll be raving about on twitter by the time we get to Utah. — John Podesta (@johnpodesta) July 7, 2017

7/7 Dude, get your head in the game. You're representing the US at the G20. — John Podesta (@johnpodesta) July 7, 2017

And Podesta fired back in a series of tweets he posted while on a cross-country road trip with his wife.