Joe Biden has extended his lead over rival Bernie Sanders in the race to become the Democratic candidate for November’s US presidential elections.
The former vice-president, who served under the Obama administration, won the Michigan primary on Tuesday as his campaign continues to build momentum after a successful Super Tuesday last week.
Biden also secured comfortable victories in the states of Missouri, Mississippi and Idaho.
Speaking in Philadelphia, Biden addressed his supporters and hailed the turnaround of his campaign thus far, after having struggled in the early primaries in Iowa and New Hampshire.
Biden issued a rallying call to Democrats across the US, saying that the party has what it takes to win the presidential election this November.
Biden said: “It’s more than a comeback, this campaign. It’s comeback for the soul of this nation.
“Tonight we are a step closer to restoring dignity and honour to the White House. We have to lead the world again.
“Donald Trump’s America First policy has made America alone.”
The latest results put Biden on 648 delegates and Vermont senator Sanders, his nearest rival, on 563.
The next set of primaries will come in a week's time when 577 delegates are available.
1,991 delegates is the benchmark needed to win the Democratic nomination.