A supporter of Bernie Sanders holds a cardboard cutout of the former US Democratic presidential candidate in Philadelphia on July 24, 2016
Philadelphia (AFP) - US Democrats scrambled to contain damaging revelations of an insider effort to hobble Bernie Sanders's presidential campaign, with the party boss abruptly announcing her resignation on the eve of the convention to officially nominate Hillary Clinton.
Debbie Wasserman Schultz said she would step down at the end of the convention, a move that aimed to put an end to the scandal threatening an uneasy truce within the fractured party.
Thousands of Democratic delegates were converging on Philadelphia, the "City of Brotherly Love," to elevate Clinton as the party's nominee who will battle Republican Donald Trump in the November election.
After a hard-fought primary campaign, the party had been heading to the Democratic National Convention seeming far more unified than the Republicans, whose fissures were laid bare last week as they confirmed brash billionaire Trump as their flagbearer.
Now the Democrats are struggling with the fallout from a scandal that threatened to mushroom into a major crisis just as the party was supposed to coalesce around its nominee.
A cache of leaked emails from Democratic Party leaders' accounts includes at least two messages suggesting an insider effort to wound the upstart Sanders campaign that had competed with Clinton -- including by seeking to present him as an atheist in deeply religious states.
Bowing to rapidly building pressure, Wasserman Schultz, the Democratic National Committee's embattled chair, announced Sunday she was stepping down at the end of the convention.
In a statement, Wasserman Schultz described Clinton as "a friend I have always believed in and know will be a great president."
Her announcement came after Sanders on Sunday repeated calls for her to go, with her leadership already under fire and impartiality called into question by the leaks.
Shortly after she resigned, Sanders said in a statement that Wasserman Schultz "has made the right decision for the future of the Democratic Party."
He called for new leadership that would "always remain impartial in the presidential nominating process, something which did not occur in the 2016 race."
Wasserman Schultz said she would still open and close the convention.
Despite the swirling political chaos, Sanders made clear he would not make an insurgent bid for the nomination.
"We've got to elect secretary Clinton," he told NBC's "Meet the Press."
More emails are expected to be released in coming days, and in an ominous sign for the party, DNC interim chair Donna Brazile indicated the drama was not yet over.
"I don't know the substance but I do know there are lots of stuff that we might have to apologize for and that's why I say you got to own it, take full responsibility and work with the staff to create a different culture at the DNC," she told CNN.
Brazile said there are likely "many thousands" of leaked emails still to come.
- 'Outrageous' -
Sanders and First Lady Michelle Obama headline day one of the Democratic convention which "gavels in" at 4:00 pm (2000 GMT) Monday.
Former president Bill Clinton is the star on Tuesday, while President Barack Obama and Vice President Joe Biden take the stage Wednesday.
Although Sanders has publicly endorsed his former rival, many of his most fervent supporters are organizing protests in Philadelphia, with the largest expected on the convention's opening day.
Several thousand protesters converged near Philadelphia's City Hall on Sunday, many of them Sanders backers and people supporting renewable energy and anti-fracking efforts.
They vented frustration over a "rigged" party system that they said was aimed at ensuring Clinton would become the nominee.
Many in the Sanders camp have also voiced disappointment with Clinton's choice of a center-left running mate, Senator Tim Kaine of Virginia, and the email revelations only fueled the resentment.
"The emails just proved what we believed to begin with," Dora Bouboulis of Vermont told AFP as she marched in a demonstration.
Trump pounced on the leaks as he tries to scoop up disaffected voters who feel Sanders -- a self-described democratic socialist initially dismissed as a fringe candidate -- was denied a fair shot at the nomination.
The provocative billionaire piled on after Sunday's announcement.
"I always said that Debbie Wasserman Schultz was overrated. The Dems convention is cracking up," he taunted on Twitter.
- 'Corrupt system' -
Clinton's campaign meanwhile was pushing the notion that Russia was behind the email leaks, in an effort to help Trump win.
"Experts are telling us that Russian state actors broke into the DNC, took all these emails, and now are leaking them out through these websites," campaign manager Robby Mook told ABC.
"It's troubling that some experts are now telling us that this was done by the Russians for the purpose of helping Donald Trump."
There was a decidedly anti-Hillary sentiment among the activists flocking into Philadelphia, where police were intensifying security operations.
"Hillary is more of a warmonger than Trump!" yelled one woman as she passed out flyers.
Hundreds of the Sanders supporters gathered near City Hall chanted "Feel the Bern!" and "This is what democracy looks like!"
But others echoed Clinton's message as she seeks to become the first female commander in chief, eight years after Obama made history as the nation's first black president.
"We shouldn't be fearful, we're Americans," delegate Patti Norkiewicz of Florida told AFP, after Trump, accepting his party's nomination in Cleveland, offered a dark vision of a nation besieged by chaos and violence.
"We should be proud, united and we're allowed to disagree," she said.