It will be “very difficult” for the UK and the EU to reach a Brexit agreement before the 31 October deadline, Irish leader Leo Varadkar has said.
He told Irish broadcaster RTE “big gaps” remained between the two sides.
Amid claims on Tuesday that talks were close to collapse, he also suggested the language around the discussions had turned toxic “in some quarters”.
Varadkar and Boris Johnson are expected to meet for further Brexit talks later this week.
The UK has said the EU needs to “move quickly” to stop it leaving without an agreement at the end of the month.
Varadkar, who spoke with Johnson by phone for about 45 minutes on Tuesday, said he would strive until the “last moment” to reach a deal with the UK, but “not at any cost” to his country, Northern Ireland and the rest of Europe.
He also downplayed the chances of any agreement being struck before the crucial summit of EU leaders on 17 October, during which next steps for Brexit are likely to be decided.
In the meantime, a source within the British Prime Minister’s office has said a Brexit deal is “essentially impossible” after a call between the PM and Angela Merkel.
Boris Johnson and the German chancellor spoke earlier about the proposals he had put forward to the EU – but the source said she made clear a deal based on them was “overwhelmingly unlikely”.
Merkel’s office said it would not comment on “private” conversations.
But the BBC’ said there was “scepticism” within the EU that Merkel would have used such language.