Deal 'possible' but tough: EU

EU President Donald Tusk said Friday that a Brexit deal in December was possible but a "huge challenge" and gave Britain's Prime Minister Theresa May 10 days to act.

Tusk issued the ultimatum after crunch talks with May on the sidelines of a Brussels summit, which the embattled British premier described as taking place in a "very positive atmosphere".

The "absolute" deadline gives May until a meeting with European Commission chief Jean-Claude Juncker on December 4 to make sufficient progress on the key Brexit divorce issues.

Failing that, the EU leaders will refuse at their next summit on December 14-15 to unlock the next phase of the Brexit negotiations, which are supposed to cover a future trade deal and a transitional arrangement after Britain leaves the EU in March 2019.

"Sufficient progress in Brexit talks at December EUCO (summit) is possible. But still a huge challenge," Tusk, a former Polish prime minister, said on Twitter after his hourlong meeting with May.

"We need to see progress from UK within 10 days on all issues, including on Ireland."

"PM May agreed to this timeframe," the source told AFP on condition of anonymity.

The EU insists that Britain must tie up three thorny divorce issues -- a multibillion-euro exit bill, the Irish border and the rights of EU nationals living in Britain -- before there can be any talks on future relations.