March 10 (UPI) -- Former Vice President Joe Biden won at least four of the six Democratic primaries held Tuesday night -- in Idaho, Michigan, Mississippi and Missouri -- while Bernie Sanders won North Dakota, and the race in Washington state is a close contest.
Biden won the top prize in Michigan, which awards 125 delegates, defeating the Vermont senator by about 250,000 votes. The former vice president won 53 delegates.
Biden also won convincing victories in Mississippi, with more than 80 percent of the vote, and Missouri. Those states awarded him nearly 70 delegates. His margin of victory was about 7,000 votes in Idaho.
Sanders picked up a handful of delegates in North Dakota, where he beat Biden with more than 53 percent of the vote. He holds a slim lead in Washington.
Following the votes Tuesday, Biden now holds a delegate count of 823 to Sanders' 663. A total of 1,991 is needed to secure the Democratic nomination at the party's convention in Milwaukee in July.
Tuesday's results continue Biden's sweeping momentum in the Democratic race. A week ago, he took over as the party front-runner after a dominating performance on Super Tuesday, when he won 10 states to Sanders' four -- including Texas.
Both candidates campaigned in Michigan on Monday, a state that will be crucial for the Democratic nominee to win in November. The state voted for Republican Donald Trump four years ago and was considered one of the key surprise victories that helped him win the presidency over Democrat Hillary Clinton.
"It's been a great night -- thank you for all of your support!" Biden said early Wednesday. "We're bringing this party together and it's going to take all of us to keep it going.
"Tonight made one thing clear: We're building the campaign that will win this nomination and defeat Donald Trump."
Former Democratic candidate Andrew Yang endorsed Biden on Tuesday night, saying "the math says Joe is our prohibitive nominee."
"I believe that Joe Biden will be the Democratic nominee and I've always said I'm going to support whoever the nominee is," added Yang, who's been working as a CNN analyst since dropping out of the race. "So I hereby am endorsing Joe Biden to be not just the nominee for the Democratic party but the next president of the United States."
Biden entered Tuesday with new endorsements, including California Sen. Kamala Harris, who's been floated as a possible running mate, and New Jersey Sen. Cory Booker. The former vice president has also received endorsements from more than 40 governors and members of Congress, plus former candidates Sen. Amy Klobuchar, former South Bend, Ind., Mayor Pete Buttigieg, former Rep. Beto O'Rourke and former New York Mayor Michael Bloomberg.
Sanders attended a roundtable event in Detroit with health officials and discussed how to best address the coronavirus outbreak.
"With the spread of coronavirus, we have already seen people hit with massive medical bills, simply for doing the right thing by getting tested. Others may face massive bills for hospitalization, treatment and quarantine if they need it. This must end. We need Medicare for all," he said.
Both Sanders and Biden canceled rallies in Cleveland on Tuesday night to mitigate the spread of coronavirus. Ohio will stage its primary next Tuesday, along with delegate-heavy states Illinois and Florida.
Michigan and Missouri held an open form of primary on Tuesday, in which voters could request a ballot for any party. The state, however, required voters to identify in writing which party they were voting for when they arrived at the polls.
Kansas City, Mo., Mayor Quinton Lucas tweeted that he was turned away from his polling place when he attempted to vote Tuesday.
"I made a video this morning about the importance of voting and then got turned away because I wasn't in the system even though I've voted there for 11 years, including for myself four times!" Lucas wrote. "Go figure, but that's okay. We'll be back later today!"
North Dakota, with 18 delegates, held a firehouse caucus, which is run by the party and allowed anyone to participate. Many voters in Washington cast their ballots by mail, which must have been postmarked no later than Tuesday.