European Council President Donald Tusk talks with Lithuanian President Dalia Grybauskaite as they attend an European Union leaders summit in Brussels, Belgium, June 28, 2018. REUTERS/Francois Lenoir

BRUSSELS (Reuters) - The chairman of the European Union summit on migration said on Friday implementing the accord agreed by 28 leaders after nine hours of hard bargaining would be the most tricky part.

“As regards our deal on migration, it is far too early to talk about a success,” Donald Tusk told a news conference after two days of talks wrapped up in Brussels.

“We have managed to reach an agreement in the European Council. But this is in fact the easiest part of the task, compared to what awaits us on the ground, when we start implementing it.”