BRUSSELS -- The European Union's chief Brexit negotiator said Friday that no major decisions were taken during the latest round of talks and warned that progress is needed in the next two weeks if the discussions are to move on to key issues like trade.

Michel Barnier said that the two days of negotiations were about "deepening" discussions on complex divorce issues, such as how much Britain should pay the EU before leaving and how the border in Ireland should work.

Barnier said that the issues of citizens' rights in each other's territories was making "some progress," but added that difficulties remain.

He said it was "imperative" to turn into concrete commitments the promise that British Prime Minister Theresa May had made that Britain would pay its financial dues before leaving the EU.

Barnier also warned that progress is needed in the next two weeks on the divorce issues if the two sides are to move on to discuss future relations - including trade - from December.

The comments came as the official who created the rules for leaving the EU said that Britain can legally stop the process any time it wants before exit day in 2019.

John Kerr, who drafted Article 50 of the EU's key treaty, said that "while the divorce talks proceed the parties are still married ... We can change our mind at any stage."

Kerr said the British government has misled voters into believing the process is unstoppable. British voters, and lawmakers, remain divided over Brexit.

May warned Friday she would not tolerate attempts "to try to block the democratic wishes of the British people by attempting to slow down or stop our departure from the European Union."

The government said it plans to enshrine in law the date and time of the U.K.'s departure - 11 p.m. on March 29, 2019 - as a protection against delay.