Joe Biden has strengthened his position as front-runner in the Democratic race to take on President Donald Trump in November’s White House election.
On March 10, he won Michigan, the biggest prize of primary voting, extending his lead over main rival Senator Bernie Sanders.
Five other states – Washington, Missouri, Mississippi, Idaho and North Dakota – voted on March 10.
The former vice-president also swept aside Bernie Sanders in Missouri, Mississippi and Idaho.
The Vermont senator won North Dakota, with results from Washington state still outstanding on March 11.
It is unclear if Bernie Sanders would fight on until the party convention in July.
The Democrats’ next big election milestone is in a week’s time when 577 delegates are up for grabs.
To secure the nomination, a candidate needs the support of 1,991 delegates. Before March 10 vote, Joe Biden had 648 to Bernie Sanders’ 563.
Joe Biden had lagged behind his Democratic rivals in early voting states, but rebounded after big wins on Super Tuesday and endorsements from several former nomination rivals.
His campaign looked all but lost at the start of the primary season in February. The 77-year-old finished a poor fourth in the Iowa caucuses and fifth in the New Hampshire primary.
However, the turn came with South Carolina – where he won due to the support of the large African-American community – and on the Super Tuesday he won 10 out of 14 states at stake, establishing a sizeable lead over Bernie Sanders.
Thanking supporters from Philadelphia on March 10, Joe Biden said Democrats, including supporters of Bernie Sanders, could beat Donald Trump.
Bernie Sanders, 78, enjoys widespread support among young voters, but has so far failed to turn that into electoral success.
The Democratic Party has been involved in a lengthy internal debate aimed at deciding which candidate has the best chance of denying President Trump a second term in office this autumn.
Once a crowded field of more than two dozen, celebrated for its women and candidates of color, the Democratic contest is now a race between two white male septuagenarians.
Joe Biden, a moderate, and Bernie Sanders, a staunch left-winger, offer starkly different visions for America’s future.