Supporters of Bernie Sanders disrupted the first day of the Democratic convention on Monday, repeatedly chanting and booing mentions of Hillary Clinton's name as the party's hopes for a show of unity dissolved into frequent chaos.
Speakers in the convention's first hours struggled to carry out business as angry Sanders supporters roared their disapproval, drawing a deafening response from Clinton delegates.
"We're all Democrats and we need to act like it," U.S. Representative Marcia Fudge of Ohio, the convention's chairwoman, shouted over the uproar.
Before the convention opened, Sanders drew jeers from his own supporters when he urged his delegates to back the White House bid of his former rival, Clinton, and focus on defeating Republican Donald Trump in the Nov. 8 presidential election.
"We want Bernie!" they shouted in anger at both Clinton's victory in the race for the Democratic nomination and emails leaked on Friday suggesting the party leadership had tried to sabotage Sanders' insurgent campaign.
The angry uproar in Philadelphia was a setback to Democrats' hopes the convention would be a smoothly run show of party unity in contrast to the volatile campaign of Republican nominee Trump.
It also was a bitter reminder of the bruising months-long primary battle between Sanders, 74, a U.S. senator from Vermont, and Clinton, 68, a former secretary of state, who this week will become the first woman nominated for president by a major U.S. political party.
Sanders tried to head off the disruptions, sending an email to delegates as the convention opened urging them not to interrupt the proceedings.
"Our credibility as a movement will be damaged by booing, turning of backs, walking out or other similar displays. That's what the corporate media wants. That's what Donald Trump wants," Sanders said in the email.
Several speakers pleaded for peace between the Democratic factions. Comedian Sarah Silverman, a Sanders supporter, said she would support Clinton "with gusto" and admonished the Sanders fans.
"To the 'Bernie or Bust' people, you're being ridiculous," she said, drawing a roar from the crowd and another round of competing cheers between Clinton and Sanders supporters.
Bernie Sanders supporters stand with tape over their mouths at the Democratic National Convention in Philadelphia, Pennsylvania, U.S. July 25, 2016.
She and U.S. Senator Al Franken of Minnesota then introduced Paul Simon to sing his 1970 classic "Bridge over Troubled Water."
Trump gloated at the Democrats' opening day disorder.
"Wow, the Republican Convention went so smoothly compared to the Dems total mess," he wrote on Twitter.
As the convention opened, the Democratic National Committee issued "a deep and sincere apology to Senator Sanders, his supporters, and the entire Democratic Party" for the email flap and said it would take action to ensure it never happens again.
Democratic National Committee Chairwoman Debbie Wasserman Schultz resigned effective at the end of the convention over the controversy. At a morning gathering of Florida delegates, Sanders supporters booed Wasserman Schultz, who they accuse of trying to sabotage the campaign of the democratic socialist.
Sanders, speaking later to his delegates in Philadelphia, also drew jeers and catcalls when he urged supporters to help defeat Trump by backing Clinton and her vice presidential running mate, U.S. Senator Tim Kaine of Virginia.
"Brothers and sisters, this is the real world that we live in," he said, adding: "Trump is a bully and a demagogue."
Members of the crowd screamed back: “So is Hillary.” "She stole the election!" someone else shouted.
The emails exacerbated the distrust of Clinton among some Sanders supporters who view her as a Washington insider who is only paying lip service to their goals of reining in Wall Street and eradicating income inequality.
But U.S. Senator Jeff Merkley of Oregon, the only senator to endorse Sanders during the primary, told the convention that supporters of the two former rivals had plenty in common.
"Whether you spent this year feeling the Bern or you spent this year ready for Hillary, all of us are ready for an America that rejects discrimination and embraces diversity, that celebrates voter empowerment not voter suppression, that creates opportunity for all of us, not just the lucky few," he said.
A supporter of former Democratic presidential candidate Bernie Sanders approaches the podium with a Sanders campaign sign as others hold up "Love trumps hate" signs towards the podium during the report of the Rules Committee at the first session of the Democratic National Convention in Philadelphia, Pennsylvania, U.S. July 25, 2016.
While Sanders has endorsed Clinton, the former first lady faces a difficult task winning over his backers in the fight against Trump. The New York businessman pulled ahead in at least one opinion poll on Monday, after lagging Clinton in most national surveys for months.
A Trump lead
A CNN/ORC opinion poll gave Trump a 48 percent to 45 percent lead over Clinton in a two-way presidential contest.
Trump was formally nominated for president at a chaotic Republican convention in Cleveland last week.
Sanders was among those due to speak on the first evening of the Democratic convention. Other scheduled speakers included President Barack Obama's wife, first lady Michelle Obama.
Ed Mullen, 49, a delegate from Illinois, said he supported Sanders but would vote for Clinton in November. He said the protesters at the convention had a right to stay.
"Democracy is messy, people have disputes with how the DNC has managed this campaign," Mullen said.
The cache of leaked emails disclosed that DNC officials explored ways to undercut Sanders' insurgent presidential campaign, including raising questions about whether Sanders, who is Jewish, was an atheist.
Sanders supporters were already dismayed last week when Clinton passed over liberal favorites like U.S. Senator Elizabeth Warren of Massachusetts to select the more moderate Kaine as her running mate.
The Clinton camp questioned whether Russians may have had a hand in the hack attack on the party's emails in an effort to help Trump, who has exchanged words of praise with Russian President Vladimir Putin. Republicans dismissed the suggestion as absurd.
The FBI said on Monday it would investigate the nature and scope of the hack.