Philadelphia: The Chairwoman of the Democratic party Debbie Wasserman Schultz on Monday resigned, hours before the party's convention, dealing a blow to hopes of demonstrating unity in the face of the threat from Republican presidential candidate Donald Trump.
Congresswoman Schultz, Chairwoman of Democratic National Committee in a statement announced her resignation after the emails leaked by Wikileaks showed that she tended to support Hillary Clinton over Bernie Sanders in the party's presidential primaries.
As head of the party, Schultz is supposed to be neutral.
Clinton, the former secretary of state, has emerged as the winner of the Democratic presidential primaries defeating Senator Sanders from Virginia.
During the primaries, Sanders campaign had alleged that the party was not staying neutral.
"Going forward, the best way for me to accomplish those goals is to step down as Party Chair at the end of this convention," Schultz, 49, said in a statement on Sunday, on the eve of the Republican National Convention.
She was the first woman nominated by a sitting president as Chair of the Democratic National Committee that would formally anoint Clinton as the party's presidential nominee.
The Trump Campaign manager Paul Manafort in a statement demanded that Clinton drop out of the race, following resignation of Schultz.
"Debbie Wasserman Schultz resigned over her failure to secure the DNC's email servers and the rigged system she set up with the Clinton campaign," he said.
"Now Hillary Clinton should follow Wasserman Schultz's lead and drop out over her failure to safeguard top secret, classified information both on her unauthorised home server and while traveling abroad.
Schultz's emails only put the Democratic Party at risk, but Hillary Clinton's emails put all of America at risk," Manafort said.
Sanders said he would continue to support Clinton as his main goal was to defeat Trump, Republican presidential candidate.
He did acknowledge his disappointment over the biased support of the top party leadership to the Clinton campaign during the primaries.
"Debbie Wasserman Schultz has made the right decision for the future of the Democratic Party. While she deserves thanks for her years of service, the party now needs new leadership that will open the doors of the party and welcome in working people and young people," he said.
"The party leadership must also always remain impartial in the presidential nominating process, something which did not occur in the 2016 race," Sanders said in a statement.
Schultz spoke to both the US President Barack Obama and Clinton before announcing her resignation.