The British parliament backed Boris Johnson's Brexit deal at an important legislative stage on Tuesday, but voted against his extremely-tight timetable.
The president of the European Council Donald Tusk said on Tuesday that he will recommend to EU leaders that they postpone Brexit beyond the current October 31 deadline.
"Following Prime Minister Boris Johnson's decision to pause the process of ratification of the Withdrawal Agreement, and in order to avoid a no-deal Brexit, I will recommend the EU27 accept the UK request for an extension," he tweeted.
"For this I will propose a written procedure," he said, which means that the 27 other member state leaders would not have to convene an emergency summit.
Mr Johnson had hoped to make the delay request unnecessary by passing the Brexit law fast enough to leave on time.
A source in his Downing Street office said there now needed be a fresh election.
"If parliament's delay is agreed by Brussels, then the only way the country can move on is with an election," the source said.
France is reportedly ready to grant an additional few days in order to facilitate the EU vote on Brexit legislation but has ruled out any extension beyond that.
The length of any extension could decide the course of Brexit.
A long delay would allow time for an election and for opponents of the divorce to push for another referendum.
A short delay might increase pressure on parliament to approve a deal.
Senior EU officials said the 27 countries that would remain in the EU after Britain leaves would "certainly not" react
Irish Taioseach Leo Varadkar welcomed the vote in favour of Johnson's legislation.
"We will now await further developments from London and Brussels about next steps including the timetable for the legislation and the need for an extension," he said.
Britain's departure from the European Union was thrown into chaos after parliament rejected Mr Johnson's extremely-tight timetable for ratifying his exit deal.
"I must express my disappointment that the House has yet again voted for delay," Mr Johnson told parliament.
"The EU must now make up their minds over how to answer parliament's request for a delay," he said.
"The government must take the only responsible course and accelerate our preparations for a no-deal outcome."
Ahead of the vote, Mr Johnson had warned parliament that if it defeated him on the timetable and forced a delay until January then he would abandon his attempt to ratify the deal and push for an election instead under the slogan of "Get Brexit Done".
"I will speak to EU member states about their intentions, until they have reached a decision we will pause this
legislation,"Mr Johnson said.
"Let me be clear, our policy remains that we should not delay."
Lawmakers voted 322 to 308 against the so-called Programme Motion which set out a three-day schedule to rush his deal through the House of Commons.
Earlier, lawmakers voted 329 to 299 in favour of the second reading of his 115-page Withdrawal Agreement Bill, a significant boost for Mr Johnson just five days after he struck a last-minute deal with the EU.
Mr Johnson said the government would pause legislation to ratify its Brexit deal with the European Union while the bloc decides whether to offer a delay to Britain's planned 31 October exit.
"I will speak to EU member states about their intentions. Until they have reached a decision we will pause this legislation. Let me be clear, our policy remains that we should not delay," he said.
Labour leader Jeremy Corbyn, who has called for a second referendum on Brexit, said Mr Johnson was trying to "blindside" MPs into supporting a "rotten bill".
He said it "fails to protect our rights and our natural world, fails to protect jobs and the economy, fails to protect every region and every nation in the UK".
London's Labour Mayor Sadiq Khan used the result to call for a second Brexit referendum.
"There is no Brexit deal which would be better for jobs and prosperity than the one we currently have with the EU," he wrote on Twitter.
"Enough is enough - the British public deserve a final say on Brexit."
News of the Brexit vote's outcome resulted in a weakening of the British Pound and a slight dip to the United States' benchmark S&P 500 stock market index.