More Than 3 Million Sign Petition Calling for Second EU Referendum, After UK Votes To Leave

— -- More than 3 million Britons and U.K. residents have signed a petition calling for a redo of the European Union referendum, just days after the United Kingdom voted to leave the bloc.

The petition, which was posted before Thursday’s vote, said the government should hold another referendum on E.U. membership if the votes for the "Leave" or "Remain" side are less than 60 percent in a turnout of fewer than 75 percent of eligible voters.

The referendum Thursday saw a turnout of 72 percent of eligible voters, with 52 percent -- or more than 17 million people -- backing a British exit, or "Brexit," and 48 percent voting to remain an E.U. member state.

The financial markets quickly reacted to the results: Around 8 a.m. local time Friday, the British stock market had plunged 7.7 percent and the German index had fallen 10 percent, according to The Associated Press. U.S. stock markets closed at three month lows on Friday.

U.K. Prime Minister David Cameron, who announced his resignation Friday after leading the failed "Remain" campaign, had said there wouldn’t be a second vote. But since the unprecedented outcome, the petition, which only British citizens or U.K. residents can sign, has garnered 2,149,429 signatures by 2:30 p.m. ET Saturday. Parliament must consider a debate on any petition posted on its website that garners more than 100,000 signatures. The government has to respond to all petitions that get more than 10,000 signatures.

The petition’s website showed a map indicating that most signatures were from people based in areas where support for the "Remain" side was strongest, including London.