US President Barack Obama on Thursday endorsed Hillary Clinton to be his successor in a video posted to her campaign's website after she secured the Democratic Party's nomination this week.

"I know how hard this job can be, that's why I know Hillary will be so good at it," he said. "In fact, I don't think there's ever been someone so qualified to hold this office."

Obama had met earlier in the day with Democratic candidate Bernie Sanders and praised him for bringing passion and supporters to the Democratic Party.

Both candidates are "patriots who love this country and share a vision for the America we all believe in," said Obama, noting the primary contest would make the party stronger against Republicans in November elections. He pointed to his own hard-fought challenge against Clinton in 2008 and noted that it didn't damage the party, but rather strengthened it.

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

He will appear at a campaign rally in Wisconsin with Clinton on Wednesday, her campaign said.

Presumptive Republican nominee Donald Trump blasted Obama's endorsement on his Twitter account.

"Obama just endorsed Crooked Hillary. He wants four more years of Obama — but nobody else does!" Trump tweeted.

Clinton responded with a put-down to Trump on the social media platform: "Delete your account."

Obama had been reluctant to jump into the race until the party's nomination was settled. Spokesman Josh Earnest had repeatedly deflected questions about when an endorsement would come.

Sanders told reporters after meeting with Obama that he would continue to campaign through the primary in the US capital on Tuesday.

He stopped short of endorsing Clinton, but said he will meet with her in the coming days and vowed to do everything he can to defeat Republican candidate Donald Trump.

"I am going to do everything in my power and I will work as hard as I can to make sure Donald Trump does not become president of the United States," Sanders said outside the White House.

White House spokesman Josh Earnest said the conversation was friendly and forward looking.

Obama congratulated Sanders on his "remarkable success" during the Democratic primaries and the men discussed the importance of the general election.

Clinton on Tuesday declared herself the party's presumptive nominee after reaching the number of delegates needed at the party convention to be named its standardbearer in November elections.

Sanders has hung on through the final contests in the hopes of convincing party officials to instead back his candidacy, despite trailing Clinton in the overall delegate count.

At a Sanders rally held in Washington Thursday evening, his supporters hailed the campaign's message and improbable success while acknowledging the end was likely near.

"At the beginning this campaign seemed hopeless, but the grassroots support he's gotten has been amazing," said Celia Byrne, 58, a Washington epidemiologist.

"We recognize reality that he won't likely be the candidate, but we hope his message will still get across." 

Latest news

Syrian opposition rules out future role for President al-Assad

The Syrian opposition said Friday it would not accept any role for President Bashar al-Assad in the future of the war-torn country, reacting to a recent US shift saying that removing al-Assad is no longer a priority for Washington.

Russian Army integrates breakaway forces of Georgian province

Parts of the small fighting forces of the Georgian breakaway province of South Ossetia have been placed under Russian military control, Russian Defence Minister Sergei Shoigu said on Friday.

Czech Republic's Pilsner Urquell beer is now Japanese

Japanese brewing company Asahi completed its takeover of the Czech brewery Pilsner Urquell on Friday, Asahi said in a statement.

Judge approves 25-million-dollar settlement of Trump University case

A US district judge on Friday approved a 25-million-dollar settlement of lawsuits and state fraud allegations against Trump University, the US president's now-defunct business venture.

Former Thai premier Thaksin to junta on reconciliation: 'Cut me out'

Former Thai prime minister Thaksin Shinawatra on Friday announced that he is not interested in the junta-led reconciliation process, three days after the junta handed him a half-a-billion-dollar tax bill for his past business deal.

Dalic: We welcome possible deal between Agrokor and banks

The government welcomes the possibility of an agreement being concluded between the Agrokor food company and creditor banks, and the bill on vitally important companies is not a fallback plan but the result of the government's care for the overall economic and financial stability of Croatia, Deputy Prime Minister and Minister of Economy Martina Dalic told a press conference in Zagreb on Friday.

Croatia, China sign action plan for cooperation in agriculture

The Croatian and Chinese ministries of agriculture on Friday signed an action plan for cooperation in the field of agriculture for the period 2017-2018, the Croatian ministry said in a statement.

ZSE indices up, Agrokor shares in focus of investor interest

The Zagreb Stock Exchange (ZSE) indices on Friday rose by more than 1.8%, with stocks of the Agrokor food and retail concern being in the focus of investor interest again.

Berlin police defend handling of Berlin market attacker

Berlin police defended themselves on Friday against accusations that they stopped surveillance on Berlin Christmas market attacker despite knowing in June 2016 he was dangerous.

Croatia, creditors tailor emergency measures to save tottering giant

Croatia's tottering retail and food giant Agrokor reached an agreement with its creditors, putting its debts standby and allowing it to continue working during emergency restructuring, the Croatian branch of Austria's Erste Bank said Friday.

Agrokor's creditors say standstill agreement to go into force today

A standstill agreement regarding the Agrokor concern's existing financial obligations to banks will take effect on Friday, additional capital will be injected into the concern in the coming days and the concern will be actively restructured, which includes a change of its management, it was said on Friday after a meeting between Agrokor's suppliers and creditor banks.

Palestinians, UN slam Israel's new settlement plan

Palestinians, Israeli activists and the UN lambasted the government of Israeli Prime Minister Benjamin Netanyahu on Friday, a day after it gave the go-ahead for the first new West Bank settlement in a quarter of a century.

South Sudan rebels release three abducted foreign oil workers

South Sudanese rebels have released three foreign engineers they abducted in early March in the oil-rich Upper Nile region, Foreign Affairs Ministry official Mawein Makol Arik said on Friday.

Turkish opposition: Imprisoned party chief has gone on hunger strike

The head of Turkey's pro-Kurdish opposition party has launched a hunger strike from prison.

European leagues threaten Champions League schedule clashes

The European Professional Football Leagues (EPFL) on Friday threatened schedule clashes on Champions League matchdays in an ongoing dispute with the governing body UEFA.

Danish court revokes citizenship of IS volunteer

A Danish appellate court on Friday stripped a man of his Danish citizenship for volunteering to fight for the extremist Islamic State in Syria.

Banks and Agrokor agree on key elements of standstill agreement

Member banks of the coordinating committee of financial creditors and representatives of the Agrokor food company have in principle agreed on key elements of a standstill agreement, which is expected to be signed later today, announcing changes in the company's management team, Erste Bank said in a statement on Friday afternoon.

Syrian man on trial in Sweden; mosque attack labelled terrorism

A Syrian man went on trial Friday in the southern Swedish city of Malmo, charged with terrorism and arson after an attack last year on a building used as an assembly hall by Shiite Muslims.