Donald Trump has endorsed US House Speaker Paul Ryan, ending a four-day stand-off which exposed deeps chasms in the Republican party over the billionaire's presidential candidacy.
Mr Trump struck a rare conciliatory tone at a Wisconsin rally, imploring his party to unite behind him and opening a full-throttle attack on Democratic candidate Hillary Clinton.
Donald Trump endorses House Speaker Paul Ryan and Sen. John McCain pic.twitter.com/rPWUh1Guad— FOX 4 NEWS (@FOX4) August 6, 2016
The tycoon declared his support for Mr Ryan in next week's US congressional primary, and declared: "Arm in arm, we will rescue the country from the Obama-Clinton disaster.
"We will have disagreements, but we will disagree as friends and never stop working together toward victory."
It is an unusual gesture for Mr Trump, who is known for his refusal to admit mistakes and his tendency to escalate matters when he is under attack.
His general election campaign has been defined by his constant attacks on fellow Republicans - a habit that has baffled party leaders, who have begged him to stay focused on his Democratic rival.
Mr Trump's refusal to back Mr Ryan had been seen by many as a final straw.
The tycoon told The Washington Post in an interview earlier this week that he was "just not quite there yet" when it came to backing the House Speaker - echoing the rhetoric used by Mr Ryan in relation to the party's presidential nominee.
In addition to praising Mr Ryan, Donald Trump also threw his support behind John McCain, saying he held the Arizona senator "in the highest esteem ... for his service to our country in uniform and in public office".
In the past, Mr Trump questioned Mr McCain's status as a war hero, and that he "should have done a much better job for the vets".
Mr Trump also endorsed New Hampshire senator Kelly Ayotte, with whom he has also sparred, calling her "a rising star".
Paul Ryan, like other top Wisconsin Republicans, did not attend Mr Trump's evening appearance in their state.
He reiterated his support for Mr Trump hours before the endorsement - but he noted that his support was not a "blank cheque", and pledged to speak out against the businessman's divisive positions if necessary.
Wisconsin governor Scott Walker also skipped the evening rally, preferring to attend an all-you-can-eat spaghetti dinner. Wisconsin Assembly Speaker Robin Vos offered a blunt message ahead of the presidential nominee's arrival: "We are Ryan Republicans here in Wisconsin, not Trump Republicans."
The Midwest unrest highlighted Mr Trump's mounting challenges during one of the most tumultuous weeks of his unorthodox campaign for the White House.
He has skipped from one misstep to the next, sparking a fresh wave of Republican defections among long-time party loyalists who refuse to support their presidential nominee - with some even going so far as to publicly support Mrs Clinton.
Eager to change their minds, the Republican nominee unleashed a torrent of insults at his Democratic rival throughout the day.
"If Hillary Clinton becomes president," he told a rally in Iowa, "you will have really, in my opinion, the destruction of this country from within."
Mr Trump called his Democratic opponent "a dangerous liar", ''an unbalanced person", ''pretty close to unhinged", ''totally unfit to lead" and lacking "the judgment, temperament and moral character to lead the country".
"In one way, she's a monster," he said in Wisconsin. "In another way, she's a weak person. She's actually not strong enough to be president."
This came soon after Mrs Clinton addressed her own political vulnerabilities while facing a group of minority journalists in Washington.
The former US secretary of state sought to "clarify and explain" a recent statement on Fox News Sunday that FBI Director James Comey said her answers to the bureau about her use of a private email server were "truthful".
"I may have short-circuited, and for that I will try to clarify," Mrs Clinton said, though still insisting she "never sent or received anything that was marked classified".
She also acknowledged that many people do not trust her.
"It doesn't make me feel good when people say those things, and I recognise that I have work to do," Mrs Clinton said.
She added: "I'm going to work my heart out in this campaign and as president to produce results for people."