European Council President Donald Tusk arrives for an EU summit in Sibiu, central Romania on May 9, 2019 | Daniel Mihailescu/AFP via Getty Images Gender balance ‘difficult to achieve’ in top EU posts, warns Tusk Council president says his goal is to reach decisions on future EU leadership by end of June.

SIBIU, Romania — Gender parity among the most senior EU positions may be "difficult to achieve," Council President Donald Tusk said Thursday.

Speaking at an EU leaders' summit, where he laid out the process for filling nearly all of the bloc's top positions in coming months, Tusk said that he would strive for geographic, demographic, political and gender balance.

Tusk stressed that in his view true balance would mean an equal number of men and women, but that he was worried this may not be possible. Currently, there is only one woman in a top EU post — Federica Mogherini, the high representative for foreign affairs. The presidents of the Commission, Council, Parliament and European Central Bank are all men.

Pressed about the balance question after the summit's closing news conference, Tusk said: "This is my intention but as you know we have just five posts and much more conditions and criteria etcetera in this. And I am really afraid that gender balance will be difficult to achieve if balance means balance — not one to four, for example."

He added, "I will do my best to build more balance than today."

Tusk announced that he was calling a special EU leaders' summit for May 28, two days after the European Parliament election, to begin formal deliberations. He said he hoped to conclude the selections by the end of June. In 2014, it took leaders four summits and until the end of August to reach a decision.

"My intention is to carry out the election of heads of the EU institutions in a swift, smooth and effective manner," Tusk said. "Naturally, this process will follow the rules set down in the treaties. It should reflect geographical balance as well as demography so that both large and smaller countries are represented in the highest positions in the EU. To me the spirit of the treaties is also important when it comes to gender as well as political balance."

Tusk also warned leaders that he would not be held hostage to the tradition of seeking consensus in such decisions, and would call a vote if necessary. The EU treaties provide for the Commission president to be nominated by qualified majority vote (then confirmed by a simple majority in Parliament), while the Council chooses its own leader by a simple majority vote.

"Of course, it would be best if we managed to reach consensus on all of these decisions but we have to be realistic," Tusk said. "I will not shy away from putting these decisions to the vote if consensus proves difficult to achieve. The aim is simple: we need effective institutions, and so we need swift decisions. My aim is for the European Council to nominate the new EU leadership in June. I call on everyone to live up to their responsibility to make this possible."