LISBON, June 20, 2016 (Xinhua) -- Portuguese Prime Minister Antonio Costa (R) and European Council President Donald Tusk hold a press conference after their meeting at Sao Bento Palace in Lisbon, Portugal on June 20, 2016. European Council President Donald Tusk warned the impact a Brexit would have on the European Union (EU) and urged British citizens to vote to stay in the European Union during his official visit here on Monday. (Xinhua/Zhang Liyun)
