Despite declaring that he would vote for Hillary Clinton in November's general election, Democratic presidential candidate Bernie Sanders maintained that he still isn't ready to endorse his primary race rival.

Asked what it would take to throw his support behind Clinton, Sanders told "CBS This Morning" that "it's not a question for me. We got 13 million votes, we got in virtually every primary and caucus the vast majority of young people - people 45 years of age or younger, and what those voters are saying to the establishment, to Secretary Clinton -- 'Hey are you gonna stand up for us? Are you gonna raise the minimum wage in fact to 15 bucks an hour?'"

When pressed why he hasn't endorsed her yet, the Vermont senator responded: "Because I have not heard her say the things that I think needs to be said."

He then laid out three positions Clinton, who has already clinched the necessary delegates to win the Democratic nomination, could stake out to win his endorsement.

"I want her to say among other things, we have a crisis in higher education -- public universities and colleges should be tuition free. Raise the minimum wage to $15 an hour," Sanders said. "I believe that healthcare should be a right of all people. I would love her to say that and I would love her to move aggressively to make that happen."

He noted that his campaign has "sat down" with Clinton's campaign to discuss the positions.

"We're talking," he told "CBS This Morning" host Charlie Rose. "I would hope that that would happen or it may not happen. It's not just me. Charlie, what this campaign has been about is people wanting to transform America."

The Democratic candidate also weighed in on the recent British vote to exit the European Union.

"I think it's a decision for the British people but I have concerns," Sanders said. "I have concerns you know when we think back over the last 100 years and the horrible wars, the kind of blood that was shed throughout Europe -- the idea of the countries coming closer together is something that we want to see."

But, he added, "a lot of people are being left behind in this global economy."