Barack Obama declared himself the winner of the democratic nomication last night, in effect ending the epic contest between him and Hillary Clinton.
Barack Obama has declared himself the Democratic nominee for US president following the end of the primary season.
The Illinois senator, who aims to be the first black president of the United States, told supporters 'another historic journey' was beginning.
His Democratic rival Hillary Clinton has refused to concede the nomination but congratulated Mr Obama for his campaign.
According to the Reuters news agency the 46-year-old now has an unassailable lead of delegates who will confirm him as the party's nominee at their convention in August.
The last two states to hold their Democratic primaries, South Dakota and Montana, were won by Mrs Clinton and Mr Obama respectively.
Speaking to cheering supporters in St Paul, Minnesota, where the Republican party will later confirm John McCain as its White House nominee, Mr Obama said: "Tonight, we mark the end of one historic journey with the beginning of another.
"Tonight, I can stand before you and say that I will be the Democratic nominee for president of the United States."
The first-term senator added: "At this defining moment for our nation, we should be proud that our party put forth one of the most talented, qualified field of individuals ever to run for this office."
Addressing her own supporters in New York Mrs Clinton stuck by her claim she would not abandon her campaign until the party's convention.
"This has been a long campaign and I will be making no decisions tonight," she said.
The New York senator has however signalled she has become more receptive to being Mr Obama's vice-presidential running-mate after telling journalists she was "open" to the idea.