The 27 European Union countries' leaders unanimously adopts the guidelines on Brexit negotiations with the United Kingdom, European Council President Donald Tusk said Saturday, during their first official summit meeting in Brussels since last month's triggering of Article 50 by the UK.Tusk stressed, at the press conference after the meeting, the outstanding unity of all the 27 countries' leaders on the guidelines for negotiations with the UK, saying they were adopted immediately after EU leaders started the summit.Tusk said the EU leaders have accepted a "phased approach" as the method of conducting the Brexit talks."Before negotiating our future relations with the UK, we must first achieve sufficient progress on citizens' rights, finances, and border issue in Ireland," he elaborated.It is too early to speculate on when this might happen, he said, adding, "it is important to highlight that it will be for the EU leaders to assess and decide if sufficient progress has been made.""We are talking about four and a half million people: Europeans residing in the UK, and Britains living on the continent," he said. "We need real guarantees for our people to live, work and study in the UK, and the same goes for the Brits."He noted that a full list of rights and benefits that the EU aims to guarantee for those affected by Brexit has been prepared by the European Commission, the executive body of the EU."In order to achieve sufficient progress, we need a serious British response. I want to assure you that as soon as the UK offers real guarantees for our citizens, we will find a solution rapidly," said Tusk.According to the European Council guidelines for Brexit negotiations, throughout the negotiations, the EU will remain unified and act as one with the aim of reaching a result that is "fair and equitable for all member states and in the interest of its citizens."While working hard to achieve that outcome, the EU "will prepare itself to be able to handle the situation also if the negotiations were to fail," the guidelines show.The EU says it will update the guidelines on Brexit in the course of negotiations as necessary.The two-year timeframe of Brexit negotiations set out in Article 50 ends on March 29, 2019.