After disappointing results in primary contests held in six states on Tuesday, Sen. Bernie Sanders held a press conference in his hometown of Burlington, Vermont on Wednesday to offer a "campaign update" and said that while the delegate math to win the Democratic presidential nomination is not in his favor, he intends to stay in the race at least through this Sunday's one-on-one debate with frontrunner Joe Biden.

"We have won the ideological debate, but we are losing the debate over electability," Sanders said in his remarks. "I cannot tell you how many people our campaign has spoken to who say they agree with us but will vote for Joe because they believe he's the best to beat Donald Trump. Needless to say, I strongly disagree with that assertion, but that's what millions of Democrats and independents say. On Sunday, I very much look forward to the debate."

Watch Sanders' complete remarks:

Sanders told reporters that he wants answers from Biden about a number of issues that the Vermont senator has centered his campaign on and that polls have confirmed are important to Democratic primary voters.

"Joe, what are you going to do for the 500,000 people who go bankrupt in our country because of medically related debt, and what are you going to do for the working people of this country and small business people who are paying, on average, 20% of their income for healthcare?" Sanders said he plans to ask Biden on Sunday. "Joe, how are you going to respond to the scientists who tell us we have seven or eight years remaining to transform our energy system before irreparable harm takes place [on] this planet because of the ravages of climate change?"

Sanders pointed out that in 20 primary states—all the states with exit poll data available—majorities of voters said in exit polls that they support Medicare for All. Exit polls in Mississippi, which Biden won by the widest margin in the primary so far, showed that 62% of voters back the proposal. Biden's healthcare proposal would leave an estimated 10 million people uninsured, according to NBC News.

"Joe, what are you going to do to end the absurdity of the United States of America being the only major country on Earth where healthcare is not a human right? Are you really going to veto a Medicare for All bill if it is passed in Congress?" said Sanders, referring to Biden's comments to that effect on Monday. 

Sanders' comments followed calls from Rep. James Clyburn (D-S.C.) and Democratic strategist James Carville Tuesday night for the cancellation of the upcoming debate in Arizona. Clyburn said the Democratic National Committee should "shut this primary down" after Biden's success in at least four states on Tuesday while Carville told MSNBC, "This thing is decided."

Biden currently has 837 delegates out of 1,991 needed to win, while Sanders has 689. A number of states with large delegate counts have yet to vote, including New York, Illinois, Pennsylvania, and Ohio.

Sanders expressed his intention to allow voters to see the two Democratic candidates in a one-on-one debate, before many cast their ballots.

"Donald Trump must be defeated, and I will do everything in my power to make that happen," Sanders said. "On Sunday night in the first one-on-one debate of this campaign, the American people will have the opportunity to see which candidate is best positioned to accomplish that goal."