Senator Bernie Sanders has suspended his campaign to become US president.
The development clears the way for former vice-president Joe Biden to become the Democratic party’s nominee.
Mr Sanders, 78, told his campaign staff about his decision on a conference call on Wednesday before addressing his supporters online.
A self-described Democratic socialist, Mr Sanders found early success making healthcare and working-class issues a key part of his election platform.
“We have transformed American consciousness as to what kind of nation we can become and have taken this country a major step forward in the never-ending struggle for economic justice, social justice, racial justice and environmental justice,” Mr Sanders told supporters in a live stream.
“Please also appreciate that not only are we winning the struggle ideologically, we are also winning it generationally.”
For a long time the front-runner, he has slipped behind Mr Biden in the party’s primaries in recent weeks.
On Wednesday, Mr Sanders congratulated Mr Biden, and said that he will work with him to “move our progressive ideas forward”.
Mr Sanders added that he will still be on ballots in states that have yet to vote in the Democratic primary elections, in order to gather delegates and influence the party’s general election platform at the convention.
“Together, standing united, we will go forward to defeat Donald Trump, the most dangerous president in modern American history.”
Mr Sanders had pursued the presidential nomination before, losing out in 2016 to Hillary Clinton.
In recent weeks, Mr Sanders had been hosting campaign events through online live streams due to health concerns from the Covid-19 outbreak.
Among the most left-leaning candidates during this year’s election cycle, the Vermont Senator campaigned on policies including healthcare for all, free public college, raising taxes on the wealthy and increasing minimum wage.
While Mr Sanders saw support from younger voters, he failed to win key African-American voters across the southern states in the Democratic primary elections.
In his announcement, Mr Sanders acknowledged the youth vote, saying: “The future of this country is with our ideas.”
“The future of our country rests with young people, and state after state, whether we won or whether we lost…we received a significant majority of the votes…from people not only 30 years or younger, but 50 years or younger.”