Washington: Hillary Clinton received a big boost to her White House ambitions after top Democrats led by President Barack Obama endorsed her amidst a latest opinion poll showing America's first woman presidential candidate ahead of her Republican rival Donald Trump.
Soon after Obama endorsed former secretary of state Clinton, the Clinton Campaign said they would canvass together in Wisconsin on June 15.
Obama's announcement came moments after he met Clinton's rival Bernie Sanders at the White House. A presidential spokesman said that the Vermont Senator, who remains defiant, was not surprised.
Sanders, 74, who would continue till the last primary in Washington DC next Tuesday, told reporters that he would work with Clinton, 68, to defeat Trump. Many believe it as an indication of his dropping out of the race next week.
"Keep in mind, we have another entire term of this potential confusion if the vote is not allowed this year. Anybody who thinks that whatever the next president - and God willing, in my view, it'll be Secretary Clinton," Vice President Joe Biden said.
Like Obama, his remarks came after he met with Sanders.
"In a meeting today, Vice President Biden and Senator Sanders discussed the importance of what Senator Sanders' campaign has done to focus the conversation in this country on income inequality, the corrosive influence of big money in our campaigns and the need to reform our politics.
"The Vice President congratulated him on energising so many new voters and bringing them into the Democratic Party. They discussed the need for the national conversation to continue to focus on the defining fight of our time," a Biden spokesman said.
Democratic Senator Elizabeth Warren also endorsed Clinton.
"Yes, I am ready to get in this fight and work my heart out for Hillary Clinton to become the next US president and to make sure that Donald Trump never gets any place close to the White House," Warren told MSNBC news channel.
Clinton, 68, now has a three-point edge over Trump, 69, (42-39 per cent) in a hypothetical matchup, Fox News said.
Presumptive Republican presidential nominee Trump's popularity has dropped by six per cent, the poll said.
The Asian American and Pacific Islanders (AAPI) described Clinton bagging the Democratic nomination as "undoubtedly historic not only because she is the first woman to be nominated for president, but because she has united diverse communities across the country in a movement toward victory".
Congressman Ami Bera, the only Indian-American in the current Congress, said Clinton would be the next US president.
Trump was highly critical of Obama's endorsement.
"Obama just endorsed Crooked Hillary. He wants four more years of Obama - but nobody else does!" Trump said in a tweet.
"Crooked Hillary Clinton will be a disaster on jobs, the economy, trade, healthcare, the military, guns and just about all else. Obama plus!" the 69-year-old New York-based real estate baron said in another tweet.