Story highlights Obama will endorse Clinton after she becomes the nominee, Mook says

"I think the President is going to back the nominee very quickly," Mook said

Washington (CNN) President Barack Obama will endorse Hillary Clinton "very quickly" after she clinches the delegates to become the Democratic nominee, Clinton's campaign manager Robby Mook said Wednesday.

Mook told CNN's Brooke Baldwin he expects Obama, who has not officially backed either Clinton or rival Bernie Sanders, to wade in once the race draws to a close after June 7. Clinton is expected to clinch the Democratic nomination on Tuesday, although Sanders maintains he has a slim chance at topping the ticket.

"I think the President is going to back the nominee very quickly," Mook said, declining to answer whether it would come right after California. "I think he'll get behind the nominee very quickly and he'll be out there campaigning vigorously."

Obama on Wednesday is giving a campaign-style speech in Elkhart, Indiana.

Mook also said he did not anticipate the need for a peace-broker who can bridge the Sanders and Clinton campaigns.

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