President Barack Obama formally endorsed Hillary Clinton to succeed him as president of the United States, calling her the most qualified person ever for the job.

For months Mr Obama had remained neutral as Mrs Clinton and Bernie Sanders, the socialist senator from Vermont, competed for the Democratic Party's nomination.

In a three-minute video Mr Obama said: "I want to congratulate Hillary Clinton on making history. I know how hard this job can be, that's why I know Hillary will be so good at it.

"In fact, I don't think there's ever been someone so qualified to hold this office. She's got the courage, the compassion, and the heart to get the job done. I have seen her judgment, I have seen her toughness up close."