Brussels has agreed the need for a Brexit extension but will not make a decision on its length until next week.
The development comes after Boris Johnson launched a fresh bid to hold a general election on 12 December, aimed at ending the stalemate at Westminster.
Meanwhile, Downing Street has said if the EU offers a Brexit delay the Government can change the date of departure through secondary legislation, known as a statutory instrument.
Political opponents had been holding out for an extension to be granted and so removing the imminent threat of a no-deal exit, before backing an election.
But it now looks as though the EU have delayed final approval until Westminster has made a decision on going to the polls.
Speaking after the two-hour meeting of EU ambassadors, European Commission spokeswoman Mina Andreeva said they “have agreed to the principle of an extension” and their work will “continue in the coming days”.
The prime minister has said he would give MPs more time to consider his Brexit deal if they backed his call for an election in the run up to Christmas.