Barack Obama endorses Hillary Clinton for president, 'fired up' to begin campaigning.

US President Barack Obama has endorsed fellow Democrat Hillary Clinton for president, saying he did not think there had ever been a nominee so qualified for the White House.

“I’m with her. I am fired up, and I cannot wait to get out there and campaign for Hillary,” Mr Obama said in a video released by the Clinton campaign.

Mrs Clinton, the presumptive Democratic nominee, said it “means the world” to her that Mr Obama has her back.

“It is absolutely a joy and an honour that President Obama and I over the years have gone from fierce competitors to true friends,” Mrs Clinton said.

Mr Obama, who enjoys strong approval ratings after nearly eight years in office, will campaign with Mrs Clinton next week in Wisconsin, her campaign said.

The endorsement increases pressure on Mrs Clinton’s rival in the Democratic primary contest, US senator Bernie Sanders, to concede the race so the party can focus on campaigning against Donald Trump, the Republican Party’s presumptive nominee for the November 8 election.

Mr Obama had been expected to support Mrs Clinton since she won enough delegates this week to clinch the Democratic nomination and become the first woman to lead a major US party as its presidential nominee.

The President remains popular with voters, and his endorsement will come as a significant boost to Mrs Clinton.

Mr Obama and Mrs Clinton were rivals during the 2008 Democratic primary that Mr Obama won.

Mrs Clinton went on to serve as Mr Obama’s secretary of state during his first term in office.

Mr Sanders, who met with Mr Obama at the White House earlier on Thursday, said afterward he would work with Mrs Clinton to defeat Mr Trump.

He said, however, that he would stay in the race to compete in the final Democratic primary vote in Washington, DC, on June 14.

Senate Democratic leader Harry Reid said Mr Sanders had accepted that Mrs Clinton is effectively the Democratic Party’s nominee, but he said Mr Sanders “needs a little time” to decide his next step.

“I didn’t hear a single word about him trying to change the fact that she’s the nominee,” Senator Reid told reporters shortly after meeting on Capitol Hill with Mr Sanders.

“I think he’s accepted that.”

This post originally appeared on ABC News.