Asked on MSNBC television whether he would vote for Clinton in November, Sanders said, "Yes, I think the issue right here is I'm going to do everything I can to defeat Donald Trump."

"I think Trump, in so many ways, will be a disaster for this country if he were to be elected president," Sanders said, calling the presumptive Republican presidential nominee a bigot and climate-change denier.

The Vermont senator said he was "pretty good at arithmetic," referring to Clinton having gained enough pledged delegates to win the nomination ahead of the party convention in Philadelphia next month. But he still has not dropped out of the race or endorsed Clinton.

Asked if he would drop out of the race, Sanders remained defiant. "Why would I want to do that when I want to fight to make sure that we have the best platform that we possibly can, that we win the most delegates that we can?" he said.

"My job right now is to fight for the strongest possible platform in the Democrat election," he said, adding he would remain in the race to push Clinton to the left.

A self-declared democratic socialist, Sanders has conducted a campaign that revolves around creating a "revolution" in what he calls a corrupt political and economic system that favors the wealthy and powerful at the expense of lower income Americans.

The Clinton and Sanders rivalry heading into the Democratic National Convention in July has split the party between its liberal and establishment wings. A Sanders endorsement of Clinton is likely to disappoint his most ardent supporters who loathe Clinton.

Multiple polls indicate low support for Clinton among liberal Sanders supporters who accuse the former secretary of state and New York senator of being too close to the establishment, hawkish and corrupt.

A June 14 poll by Bloomberg found only 55 percent of Sanders supporters would vote for Clinton, while 22 percent said they would vote for Trump and 18 percent for Libertarian Gary Johnson.

If Sanders supporters jump the Democratic ship and vote for Trump, or engage in a protest vote by supporting Johnson or Green Party candidate Jill Stein, that would undercut support for Clinton at the national level and split Democratic votes.

To pull Sanders supporters to her camp, analysts speculate she may tap for vice president Senator Elizabeth Warren, a progressive liberal who has an anti-Wall Street track record.

An average of 10 polls conducted in June show Clinton with a nearly 6-point lead over Trump, according to RealClearPolitics.

cw/jm (AFP, AP, dpa)