EU ambassadors are to meet to discuss what length of Brexit extension to offer the UK, as MPs consider Boris Johnson’s call for an early election.
Most EU states are understood to favour a three-month delay, with an option to end earlier if a deal is ratified sooner than this by Parliament.
But France has argued for a shorter extension to the 31 October deadline.
It comes after the PM said he would give MPs more time to debate his Brexit deal if they backed a 12 December poll.
The government has said it plans to bring forward a Commons vote on an early general election on Monday if the EU offers a delay until January, as is widely expected.
But the chances of enough MPs backing the motion - which under the Fixed-Term Parliaments Act requires the support of two-thirds of MPs - appear uncertain, with Labour not committing to how it plans to vote.
On Thursday night, there were reports the party’s official position was to abstain on the vote, ending any chance of it gaining enough support.
But in an interview later, leader Jeremy Corbyn said: “Take no deal off the table, and we absolutely support an election.”
The EU’s decision on what length of extension to offer - which will be discussed in a closed-door meeting in Brussels on Friday morning - comes after Mr Johnson was compelled by a law passed by MPs to send a letter to the bloc requesting a delay.
Before sending the letter on Saturday, he had repeatedly promised the UK would leave the EU by Halloween.
The letter, which the prime minister was made to send by the so-called Benn Act, calls for Brexit to delayed until 31 January 2020.
On Thursday, Mr Johnson reiterated he did not want a delay but his preferred option if one was granted was for it to be short - “say to 15 or 30 November”.
In a letter written to Mr Corbyn calling for an election, Mr Johnson said if a shorter delay was granted he would try to get his deal through Parliament again, with Labour’s support.
BBC European correspondent Kevin Connolly said most EU states were prepared to agree an extension until 31 January 2020, with the option for it to end sooner if MPs in the UK ratify a Brexit deal before then.
He said the EU had hoped the decision on the length of delay would be made on Friday, though it was possible it could be moved until early next week to allow events at Westminster to unfold.
A stand-off could emerge, he added, where the EU wants to wait to see how Parliament reacts to the election proposal, while MPs want to first see what sort of extension will be offered.
Our correspondent added that there could be an emergency summit in Brussels on Monday to allow leaders to reach an agreement if no decision was made on Friday.
‘Take no-deal off the table’
Responding to Mr Johnson, Mr Corbyn said on Thursday: “Take no-deal off the table and we absolutely support a general election.
“I’ve been calling for an election ever since the last one because this country needs one to deal with all the social injustice issues - but no-deal must be taken off the table.
“The EU will decide whether there is an extension… and then we can decide.”
Should enough MPs back an election, they would have until 6 November to debate Mr Johnson’s Brexit deal, the government has said.
Mr Johnson said it would be “morally incredible” if opposition MPs refused to go along with his plan.
It comes after MPs voted on Tuesday to back the first stage of the prime minister’s Withdrawal Agreement Bill - putting the deal he agreed with Brussels into law - but rejected his plan to push it through the Commons in three days.
Boris Johnson cannot be remotely sure Labour and the smaller parties will let him have his way. The SNP and the Lib Dems are both tempted to go for an election as soon as a three-month delay is agreed.
The Labour Party’s official position has always been that they would agree to an election. In fact, officially, they are chomping at the bit, like the other parties, as long as a delay is agreed.
One senior member of the shadow cabinet predicted they would not be able to withstand the pressure if the Lib Dems and the SNP said yes.
Jeremy Corbyn himself, and certainly one group in his camp, are understood to be very tempted, too. But, just as in 2017, lots of Labour MPs are horrified at the idea, partly because of Labour’s standing in the polls.
But also, there are senior shadow cabinet ministers who believe the smart thing would be to leave the PM in his purgatory, twisting, unable to get his bill through, unable to get to an election.
Where parties stand on election
- Conservatives - Boris Johnson has requested an election twice already - but not all of his MPs are on board with the idea, arguing that the focus should be on delivering Brexit first
- Labour - Has insisted it wants an election but won’t vote for one until a no-deal Brexit has been firmly taken off the table. Some of its MPs from Leave voting areas may take a different view
- SNP - The party’s leader at Westminster, Ian Blackford, said “we want an election but these terms are not acceptable,” adding that the poll should take place earlier than the middle of December
- Lib Dems - Would prefer another referendum but have said they would vote for an election if there was a long enough extension. Leader Jo Swinson said she wanted to see what the EU said on Friday before deciding
- DUP - Sammy Wilson, the party’s Brexit spokesman, has indicated that the unionists could support an election in a bid to secure better terms with the EU
- Independent Group for Change - Leader Anna Soubry said an election “wouldn’t solve anything” and called again for another referendum
- Plaid Cymru - The party’s four MPs are likely to vote against an election, with the party arguing for another referendum instead
- Green Party - The party’s sole MP, Caroline Lucas, looks set to vote against an election, saying in a tweet the UK could still “crash out” with no-deal if MPs can’t amend the Withdrawal Agreement