European Council President Donald Tusk told the European Parliament on Wednesday that he would be ready to call a special summit on Brexit whenever negotiators said "decisive progress" had been made toward a deal.

Briefing lawmakers on last week's regular summit, Tusk recalled that EU leaders had agreed that they would meet again to endorse a deal if their negotiator Michel Barnier judged that enough progress toward a deal had been made. A meeting pencilled in for November 17-18 is still on hold.

"I stand ready to convene a European Council, if and when the Union negotiator reports that decisive progress has been made," Tusk said. "The Brexit talks continue with the aim of reaching a deal," he added, saying no one wanted talks to fail.

He repeated that he believed leaders would extend Britain's status-quo transition period after Brexit in March if London asked for that - an issue May raised at the summit.

"It was made clear by the UK that more time is needed to find a precise solution," Tusk said. "Therefore, there is no other way but to continue the talks. Leaders expressed their full trust and support for Michel Barnier."