European Council President Donald Tusk (R) and European Commission President Jean-Claude Juncker attend a press conference after a summit of the 27 EU leaders excluding British prime minister in Brussels, Belgium, on Feb. 23, 2018. It will be "really difficult" for the European Union (EU) leaders to agree on the post-Brexit multiannual EU budget this year, European Council President Donald Tusk said Friday. (Xinhua/Ye Pingfan)