Just as Iceland’s newly-elected prime minister signals her desire to join the European Union, the block will assess on Monday how to solve a maritime border dispute between Slovenia and Croatia that is disrupting plans to admit any new members.

Olli Rehn, the 27-nation bloc’s enlargement commissioner, will brief foreign ministers from EU states on his efforts to broker a solution to the dispute, which threatens to torpedo Croatia’s ambitions of completing its EU accession talks by the end of this year.