European Union Brexit negotiator Michel Barnier says British Prime Minister Theresa May should endorse a Labour-backed permanent customs union with the bloc to break the impasse over their divorce.
Barnier on Monday told a Luxembourg news conference time was "extremely short" to conclude a deal before Britain leaves the EU on March 29.
He then met UK Brexit Secretary Stephen Barclay for what both sides said were "constructive" talks in Brussels.
"It's clear from our side that we are not going to reopen the withdrawal agreement but we will continue our discussion in the coming days," Barnier said.
The EU is urging May to work with UK Labour leader Jeremy Corbyn to unlock ratification of the withdrawal agreement she negotiated with Brussels.
British lawmakers overwhelmingly rejected the deal, agreed in November, in a vote last month, leaving Britain on course for an abrupt "no-deal" Brexit.
"I found Corbyn's letter interesting in tone and in content," Barnier said earlier in the day in Luxembourg of the Labour leader's Brexit proposals, sent to May.
"Something has to give on the British side."
In a reply to Corbyn published late on Sunday, May rejected the idea of a customs union, saying Britain must be able to strike post-Brexit trade deals.
Barnier said he understood May did not want to delay Brexit to win more negotiating time and reiterated the controversial Irish border fix - or "backstop" - was an insurance policy the EU hoped never to use.
Barnier said it was up to London to provide clarity on what is next.
Australian Associated Press