US President Joe Biden has said he is ready to pass the torch to new Democratic presidential nominee Kamala Harris, as he prepares to give a bittersweet farewell address to the party's convention in Chicago.
Protests against Israel's war in Gaza had threatened to overshadow the occasion, but only a few thousand demonstrators turned out instead of the tens of thousands that organisers had predicted.
The speech will nevertheless be one of the most difficult moments in President Biden's long career, as the 81-year-old faces the party that pushed him out of the White House race less than a month ago after a disastrous debate with Republican candidate Donald Trump.
But while he finds himself consigned to being the convention's warm-up act instead of its star, Mr Biden is also expected to receive a hero's welcome as Democrats thank him for stepping aside for Ms Harris.
The first female, black and south Asian vice president in the US has turned the race upside down, breathing new life into the Democratic Party and wiping out Mr Trump's lead in the polls.
"I am," Mr Biden told reporters when asked if he was ready to pass the torch to Ms Harris, as he did a sound check at the convention centre.
She is expected to appear briefly on stage with the president and give her own hugely anticipated speech at the culmination of the convention on Thursday.
Meanwhile, Mr Trump tried to drag the attention back to himself with a rally in the battleground state of Pennsylvania in which he highlighted what he called Ms Harris' "craziness" and said she "has no idea what the hell she's doing" on the economy.
The White House said President Biden is continuing to fine-tune his speech after his arrival in Chicago and "looks forward to addressing his party and the nation."
"It is a fulfilling moment for him and he's excited," Press Secretary Karine Jean-Pierre told reporters travelling with the president on Air Force One.
He will have his family behind him too, with his daughter Ashley and wife Jill set to introduce his primetime speech to thousands of delegates.
Former secretary of state and first lady Hillary Clinton, who lost to Mr Trump in the 2016 election, will also address the convention at the heavily secured United Center in Chicago.
Police have set up a ring of steel around the venue to ward off protests against the Biden-Harris administration's support for Israel since the 7 October Hamas attacks.
More than 1,000 people gathered in Chicago's Union Park chanting "free, free Palestine" as helicopters flew overhead and motorists beeped their horns in support of the pro-Palestinian gathering. Protesters gathered in smaller numbers elsewhere.
A small group of around 100 demonstrators broke off from a larger march involving thousands of people and targeted the metal barriers surrounding the United Centre on the first day of the party gathering.
Police in blue helmets with shields and carrying black batons prevented them from getting to the inner cordon. One demonstrator clad in black was carried out by their arms and legs by several officers, an AFP correspondent saw.
Executive Director of the immigrant campaign group Voces de la Frontera (Voices from the Border) Christine Neumann-Ortiz said that "our commitment to defeating fascism does not mean we do not make demands of the Democratic Party".
But while at least one speaker said they were hopeful that as many as 50,000 people would participate as the day wore on, there was no sign of that number turning up.
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The day will undoubtedly bring mixed emotions for Mr Biden, who has watched Ms Harris chase down Mr Trump in the polls and enthuse voters in a way that he never achieved during his time as candidate.
Reports have suggested that the president remains bitter at top Democrats, including former US House of Representatives speaker, Nancy Pelosi for pushing him out of the contest.
But as he sees out the last months of his presidency, he will be all too aware that his legacy hinges on whether Mr Harris can beat the 78-year-old former president and that, if she does not, many will blame him for clinging on so long.
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Delegates gathering in Chicago are already preparing for an emotional farewell.
"Tonight we honor President Joe Biden and his legacy," said Luciano Garza, 61, from south Texas.
"It's surreal, it's very sad, but we're hopeful, and what he has done is pass the torch on to Kamala Harris, who will continue his legacy and her own policies."
Mr Trump, meanwhile, has been sent into a tailspin by what he calls the "coup" by the Democratic Party.
While Democrats meet in Chicago, the Republican is crisscrossing the country, with rallies scheduled in Michigan, North Carolina and Arizona this week.
In another attempt to shift attention from Ms Harris, Republicans in the House of Representatives lodged a formal impeachment report against Mr Biden.
It accuses the president of corruption linked to his son Hunter Biden's foreign business affairs.
