Hours after Hillary Clinton declared herself the presumptive presidential nominee for the Democratic Party, Sen. Bernie Sanders’ (I-VT) campaign fired off a statement warning that she spoke too soon.

“In the past three weeks voters in Indiana, West Virginia and Oregon respectfully disagreed with Secretary Clinton,” communications director Michael Briggs said in a statement. “We expect voters in the remaining eight contests also will disagree. And with almost every national and state poll showing Sen. Sanders doing much, much better than Secretary Clinton against Donald Trump, it is clear that millions of Americans have growing doubts about the Clinton campaign.”

Sanders’ team was responding to comments Clinton made in a CNN interview that aired Thursday, in which she said there was “no way” she wouldn’t earn her party’s nomination.

“I will be the nominee for my party, Chris,” she told host Chris Cuomo. “That is already done in effect. There is no way I won’t be.”

Tensions between the two campaigns have escalated as Clinton edges closer to the number of delegates needed to secure the nomination outright, while Sanders has pledged not to leave the race until the Democratic National Convention this July in Philadelphia.