U.S. President Barack Obama has officially endorsed Hillary Clinton, his former secretary of state, for president.

Obama gave his endorsement in a video published online.

"I want to congratulate Hillary Clinton on making history as the presumptive Democratic nominee for president of the United States."

In the video, he said he knows "how hard this job can be," and that he knows Hillary "will be so good at it."

"In fact, I don't think there's ever been someone so qualified to hold this office," he said. Specifically, Obama said Clinton has the "courage, compassion and heart to get the job done.

"I am fired up and I cannot wait to get out there and campaign for Hillary," Obama said.

Clinton responded to the endorsement in an interview with Bloomberg Politics.

"It just means so much to have a strong, substantive endorsement from the president. Obviously I value his opinion a great deal personally," she said. "It's just such a treat because over the years of knowing each other, we've gone from fierce competitors to true friends."

With a high approval rating of over 50 percent, Obama is seen as a valuable campaign tool for Clinton. The Clinton campaign said Obama will join Clinton to campaign in Green Bay, Wisconsin next week.

Sanders remains in the race

The endorsement came after Obama met with Clinton's Democratic rival, Vermont Senator Bernie Sanders, Thursday at the White House.

In the endorsement, Obama also congratulates Sanders on an "incredible" campaign and for getting more people involved in the political process.

Obama also thanked Sanders for highlighting important issues such as economic inequality, excessive money in politics and bringing young people into the process.

Clinton received enough delegates to capture the Democratic nomination this week after major primary wins on Tuesday. But Sanders told reporters Thursday he is looking forward to the last Democratic primary of the campaign in the District of Columbia on Tuesday.

He also spoke about the main issues he plans to bring to the Democratic National Convention in Philadelphia at the end of July. The Democratic Party will officially choose its nominee at the convention.

Sanders said he spoke with Clinton after her victories this week to congratulate her on a "very strong campaign.

"I look forward to meeting with her in the near future to see how we can work together to defeat Donald Trump. And to create a government which represents all of us, and not just the 1 percent."

Sanders also took the opportunity to criticize Trump, whom he said would be a "disaster" as president of the United States.

I'm Bryan Lynn.

Chris Hannas reported on this story for VOANews. Additional information came from the Associated Press and Reuters. Bryan Lynn adapted it for Learning English. Hai Do was the editor.