LONDON -- European Council President Donald Tusk on Thursday urged British Prime Minister Theresa May to start the process for her country to leave EU as soon as possible.

Speaking at the start of their meeting at the No. 10 Downing Street, Tusk also said "the ball is now in your court" as they discussed the next steps on Brexit, according to British press reports.

Tusk said the other EU members were waiting to see when May would trigger the Article 50 of the Lisbon treaty which formally launches Britain's exit from the EU.

"I'm aware that it is not easy but I still hope you will be ready to start the process as soon as possible," he said.

A spokeswoman for May said that the British prime minister stressed to work together with Tusk so that there was a "smooth process" for leaving EU.

Up to now, May has refused to pin down a specific date to trigger the article 50, saying that her government needs time to prepare for negotiations.

EU leaders, excluding Britain, will meet next week in Bratislava to sketch out the bloc's future strategy after Brexit.