We're continuing to get reaction to Biden's decision to exit the presidential race, with Canadian Prime Minister Justin Trudeau praising Biden as a "great man" who is "guided by his love for his country".

In a statement on X, he writes: "As President, he is a partner to Canadians - and a true friend.

"To President Biden and the First Lady: thank you."

Courtney Subramanian
Reporting from Washington DC

President Biden's aides had been planning campaign events next week upon his return to the White House before he announced his decision to end his election campaign.

The president informed senior White House and campaign aides of his decision to exit the 2024 race shortly before the letter was publicly released, according to a senior White House official.

He told his team he had been reflecting on it over the past couple of days. The decision was "closely held," the official tells the BBC.

Image source, Reuters

She's received an endorsement from Joe Biden to be the Democratic pick for presidential nominee – but who is Kamala Harris?

Harris, vice-president of the US, was the first woman and the first black person to serve as California's attorney general, the top lawyer and law enforcement official in America's most populous state.

She gained a reputation as one of the Democratic Party's rising stars, coming to power after being elected as California's junior US senator in 2017 before setting her sights on the presidential nomination in 2020.

However, her adept debate performances were not enough to compensate for poorly articulated policies.

It was Biden who returned the now 59-year-old to the national spotlight by putting her on his ticket as the Democrat vice-presidential candidate in that same race.

After Biden and Harris won the election, she focused on several key initiatives and has been instrumental in some of the Biden administration's most touted accomplishments, including the launch of a nationwide "Fight for Reproductive Freedoms" tour, highlighting harm caused by abortion ban, and calling on Congress to restore the protections of Roe v Wade for abortion rights.

While she struggled to achieve broad appeal among Americans, in recent weeks – as speculation about Biden swirled – she has found a renewed base of support.

• Read more about Harris here

Image source, Getty Images

There's been a flood of reaction from around the US – and the world – after Joe Biden announced earlier that he was ending his campaign to be re-elected as US president.

Here's how the last couple of hours have played out:

• Biden has endorsed Vice-President Kamala Harris to become the Democratic candidate in the November election. She's described his decision as a "selfless and patriotic act"
• Biden said he was making the call "in the best interest of my party and the country", and has promised more detail when he addresses the country later in the week
• The president came under intense pressure from fellow Democrats after a faltering debate performance against his political rival Donald Trump in late June. Trump says Biden is "not fit to serve"
• Barack Obama, the former US president under whom Biden served as vice-president, described him as a "patriot of the highest order". Obama is among the top Democrats reported to have expressed concern about Biden's electoral chances, as is former House Speaker Nancy Pelosi
• Others in Trump's Republican Party, including current House Speaker Mike Johnson, have suggested Biden should resign
• Biden's received praise from other political allies and Western leaders, including UK Prime Minister Keir Starmer, who commended Biden for making a difficult decision "in the best interests of the American people"

Bernd Debusmann Jr
Reporting from the White House

We've just received another statement from the White House, in which they insist that Biden will finish his current term in office despite stepping down as a candidate.

The statement says Biden "inherited an economy in freefall, a skyrocketing violent crime rate, and alliances in tatters from his predecessor."

"He turned that around to deliver the strongest economic growth in the world and the lowest violent crime rate in nearly 50 years, while making Nato bigger than ever," it adds.

"He looks forward to finish his term and delivering more historic results for the American people."

Over the course of the last few days – and hours – several Republicans have suggested that if Biden is not capable of running again, he should also step down as president.

So far, there has been no suggestion that he has even considered such a move.

Details of the lead up to Joe Biden's announcement that he'd be withdrawing from the presidential race are still emerging.

Biden called Kamala Harris, his vice-president, and the two spoke multiple times before he made public his decision, a person familiar with the call tells the BBC.

Australian Prime Minister Anthony Albanese has praised Joe Biden for his "leadership and ongoing service".

In a post on X, Albanese writes: "The Australia-US Alliance has never been stronger with our shared commitment to democratic values, international security, economic prosperity and climate action for this and future generations."

Bernd Debusmann Jr
Reporting from the White House

We've just received a statement from Republican National Committee chairman Michael Whatley and co-chairman Lara Trump, the former president's daughter-in-law.

In the statement, the pair say that Trump will win the election "because he is the only person who will rebuild our southern border, restore our economy and secure our standing in the world."

"Every single failure we’ve seen from Joe Biden – the Afghanistan withdrawal, a border crisis, crushing inflation, and America weakened abroad – has been delivered hand-in-hand with Kamala Harris," the statement adds.

It goes on to say Harris would "be a disaster in the White House" and it accuses her of helping "Biden cover up his declining health while in office".

Bernd Debusmann Jr
Reporting from the White House

Like much of the American public –and many, many journalists – some White House staffers say they were caught by surprise, first learning of President Biden's decision via X, the platform formerly known as Twitter.

I just briefly spoke to one acquaintance who works for the White House, who said he was out with friends when he saw the news on his feed.

"That was the first I heard," said the staffer, who asked not to be identified by name. "It's not totally unexpected I guess, but came quicker than I'd have thought."

Similarly, Politico and other US media outlets have reported that even senior aides - including senior advisor Anita Dunn - were caught unawares by the announcement.

"We're all finding out by tweet," an unidentified Democrat was quoted as saying. "None of us understand what's happening."

Politico noted that a fundraising email from "Joe and Kamala" was emailed to supporters at 1354 EST (1754 GMT) - nearly ten minutes after Biden's announcement was published on X.

Phil McCausland
Reporting from New York

Donald Trump Jr, the former president's son, was one of the first to direct Republican attack lines towards Harris.

"Kamala Harris owns the entire leftwing policy record of Joe Biden. The only difference is that she is even more liberal and less competent than Joe, which is really saying something," he said on X, formerly Twitter.

Many on the right attacked her track record on the US southern border, as she was directed to lead America's immigration policy.

Republican Governor Greg Abbott of Texas, who has frequently been criticised for his hardline immigration positions, attacked her record on immigration.

"Joe Biden has now endorsed and fully supports his 'Borders Czar' Kamala Harris to be the Democrat candidate for president," he wrote on social media. "I think I will need to triple the border wall, razor wire barriers and National Guard on the border."

Marjorie Taylor Greene, a Republican lawmaker known for making controversial statements, joined other Trump allies in dismissing any candidate who intended take on Biden's mantle.

"Kamala. Michelle. Hillary. It doesn’t matter who they pick," Greene says. "President Trump is the strongest he’s ever been and you can’t stop the TRUMP TRAIN."

Another key Western ally, German Chancellor Olaf Scholz, says Biden has "achieved a lot: for his country, for Europe, for the world".

"Thanks to him, transatlantic cooperation is close, Nato is strong and the USA is a good and reliable partner for us. His decision not to run again deserves respect."

Image source, EPA

More now from Kamala Harris, who's issued a statement after learning that Joe Biden has ended his bid for re-election and endorsed her to become the Democratic candidate in the November presidential election.

She thanks Biden for his "extraordinary leadership" and "decades of service to our country".

Recounting how she met the president, she goes on to write of his "honesty and integrity... his love of our country and the American people".

She describes his decision to end his re-election bid as a "selfless and patriotic act" and says she is "honoured" to have Biden's endorsement.

We've just heard from Vice-President Kamala Harris, who has Biden's endorsement to take the Democratic nomination into the presidential election in November.

She writes: "I will do everything in my power to unite the Democratic Party—and unite our nation—to defeat Donald Trump and his extreme Project 2025 agenda."

“We have 107 days until election day. Together, we will fight. And together, we will win.”

Nomia Iqbal
North America correspondent

Former President Barack Obama’s statement pays tribute to President Joe Biden, who faithfully served as his vice president for eight years.

But one thing is hugely noticeable: he doesn’t endorse Kamala Harris.

Instead, he says: “I have extraordinary confidence that the leaders of our party will be able to create a process from which an outstanding nominee emerges.”

Biden didn't endorse Harris in his initial statement, but did so an hour later in a post on X.

Image source, Reuters

"Joe Biden has been one of America’s most consequential presidents, as well as a dear friend and partner to me," writes Barack Obama on X.

"Today, we’ve also been reminded – again – that he’s a patriot of the highest order," Obama continues.

Obama appointed Biden as his deputy during his time in office. But during the recent period of pressure on Biden, he reportedly joined other senior Democrats in urging him to consider his position.

And moments after Keir Starmer reacts, his predecessor Rishi Sunak follows suit.

Writing on Twitter/X, the former PM and Conservative Party leader says that while working with Biden, he "saw first-hand his love for America and dedication to service".

"Our partnership has led to significant achievements, including Aukus, steadfast support for Israel and joint efforts in defending our people from Houthi threats," he adds.

"I wish him all the best."

Image source, EPA

We've just heard from UK Prime Minister Keir Starmer now.

In a statement, he says he "respects" Biden's decision and looks forward to working with him during the final months of his presidency.

"I know that, as he has done throughout his remarkable career, President Biden will have made his decision based on what he believes is in the best interests of the American people," he adds.

The pair met for the first time around two weeks ago, at a Nato summit in Washington where Biden accidentally referred to Ukrainian President Volodymyr Zelensky as "President Putin".

Image source, Reuters

Another senior Democrat, Nancy Pelosi, pays tribute to Biden's achievements in office.

In a post on X, the former House Speaker calls him "a patriotic American who has always put our country first".

Echoing the words of other top members of her party, she calls him "one of the most consequential presidents in American history".

Just last week, Pelosi is said to have presented Biden with information suggesting that he could not win the White House again, piling further pressure on.

Biden has endorsed his deputy Kamala Harris as his replacement for Democratic nominee. But that's not a done deal and things will play out in the coming days.

A short time ago, we mentioned Gavin Newsom, who is one of the names talked about as a potential successor to Joe Biden.

Here are some of the other key names in the frame:

Image source, EPA

Kamala Harris

The vice-president has Biden's endorsement - echoed by the Clintons moments ago.

She proved to be a loyal deputy during the recent weeks of pressure. Since they took the White House in 2020, she has become the face of the administration's campaign to protect reproductive rights.

Image source, Reuters

Gretchen Whitmer

The Michigan governor is an increasingly popular Midwest Democrat who many pundits had been speculating as a presidential candidate for 2028.

She has campaigned for Biden in the past and has not been shy about her political aspirations. But for now, she says her job "remains the same".

Image source, Reuters

Gavin Newsom

The governor of California has been quick out of the blocks to praise Biden as "one of the most impactful and selfless presidents" America has known.

He, too, has been suggested as a potential candidate for the White House in 2028, having become one of the Biden administration's fiercest surrogates who raised his national profile in recent years.

Image source, Reuters

Pete Buttigieg

It's no secret that the transportation secretary has presidential aspirations.

He ran for the White House in 2020 and is often touted as one of the Biden administration's best communicators. He's had to deal with a number of crises while in office.

• Read more on all the potential candidates here.

Bill Clinton, the former US president, and his wife Hillary Clinton, who ran against Trump in 2016, have endorsed Kamala Harris.

In a statement posted on X, external, they say they will do "whatever they can to support her".

"Now is the time to support Kamala Harris and fight with everything we've got to elect her," they add.

The premier power couple of American politics take a decidedly combative tone against Trump.

"We've lived through many ups and downs, but nothing has made us more worried for our country than the threat posed by a second Trump term," they say.

"He has promised to be a dictator on day one, and the recent ruling by his servile Supreme Court will only embolden him to further shred the Constitution."

Image source, Getty Images