European Council President Donald Tusk said on Monday that delaying Brexit beyond the scheduled exit date of March 29 would be a "rational solution".
Speaking after the EU-Arab League summit in Egypt's Red Sea resort of Sharm el-Sheikh, Tusk said he spoke with British Prime Minister Theresa May about "issues including the legal and procedural context of a potential extension."
"It's, for me, absolutely clear that there's no majority in the House of Commons to approve a deal. We will face an alternative — a chaotic Brexit or an extension," he said.
"The less time there is until 29 March the greater the likelihood of an extension. This is an objective fact, not our intention, not our plan but an objective fact.
"I believe in the situation we are in an extension would be a rational solution, but Prime Minister May believes she is still able to avoid this scenario."
The UK is still set to leave the EU on March 29 but as the British parliament has not yet approved a Brexit deal there is growing concern it will not be ready to leave the bloc by that date.
May is under pressure to seek a delay for Brexit from several of her cabinet ministers. On Sunday, she said parliament would vote on Brexit by March 12 at the latest.