Trump's foreign policies harming America's global standing - Biden
Former US vice president Joe Biden has blasted President Donald Trump's performance on the world stage as erratic and extreme.
Mr Trump, Mr Biden told an audience in New York, has damaged America's "reputation and our place in the world, and, I quite frankly believe, our ability to lead the world".
The Republican president has unsettled Washington's allies by withdrawing the United States from the Paris climate accord, a nuclear deal with Iran and a trans-Pacific trade agreement, and has also threatened to leave Nato.
Mr Biden, who served eight years as Barack Obama's vice president and 35 years in the Senate, was making his first major foreign policy address as a Democratic presidential candidate.
It was a much-needed return to firmer ground for the 76-year-old after weeks of having to defend his civil rights record, allowing him to train his attention on Mr Trump rather than Democratic rivals for next year's election.
Mr Biden has seen some erosion in support from Democratic voters, with Kamala Harris, a black senator from California, largely reaping the benefit.
In his address at the Graduate Centre at the City University of New York, Mr Biden criticised the president for abdicating the United States' leadership role in the world and argued collective action is necessary to confront threats posed by climate change, nuclear proliferation, terrorism and cyberwarfare.
"We must once more harness that power and rally the free world to meet the challenges facing us," Mr Biden said. "It falls on the United States of America to lead the way."
As president, he said he would pull most US troops out of Afghanistan, end American support for Saudi Arabia's military intervention in Yemen and reaffirm the nation's commitment to Nato.
Mr Biden reaffirmed his support for the security of Israel "regardless of how much you may disagree with its present leader" - a shot at Prime Minister Benjamin Netanyahu.
Domestically, Mr Biden would terminate Mr Trump's travel ban against people from Muslim-majority countries and end the practise of separating migrant families at the border with Mexico.
Mr Biden has sharply criticised the president for walking away from the 2015 international nuclear deal with Iran, which Mr Biden would reinstate should Tehran comply with its provisions.
He would also have the US rejoin the Paris Climate Accord and convene a global summit on climate change.
Mr Biden would also push for more ironclad commitments from North Korea to abandon its nuclear programme than Mr Trump has demanded.
"Above all, diplomacy requires credibility," Mr Biden said. "Donald Trump has absolutely corroded our country's credibility."
Ahead of Mr Biden's speech, the Republicans released lengthy critiques of his judgment on foreign affairs, pointing out that he advised Mr Obama to not go forward with the 2012 raid that killed Osama bin Laden.