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President Barack Obama has formally endorsed Hillary Clinton in the presidential race. 

The endorsement was rumored for the past few days and the official video message came out just after Obama met with Bernie Sanders at the White House. 

Obama touted the difficulties of holding the office and said he knows "Hillary will be so good at it."

"I don't think there's ever been someone so qualified to hold this office," he said.

Clinton clinched the nomination earlier this week with victories in California and New Jersey. 

Sanders has vowed to stay in the race, saying he will campaign ahead of Tuesday's primary in D.C.

The White House said President Obama will be on the campaign trail with Clinton next week in Green Bay, Wisconsin.

Watch the video above. 

Donald Trump responded on Twitter: 

Then, Clinton hit back: