European Union leaders have pulled an all-nighter at a summit but failed to agree on the list of candidates for the bloc’s key posts, with the marathon talks entering a second day.

The leaders trickled in for bilateral contacts throughout Sunday before officially convening at around 8pm.

They have been locked in talks ever since amid deep divisions over how best to balance political, geographic and gender considerations among the 28 member nations.

With the selection process bogged down for the second EU summit meeting in a row, the leaders are still considering Dutch socialist Frans Timmermans to replace Christian Democrat Jean-Claude Juncker as president of the EU’s powerful executive arm, the European Commission.

“Let’s see,” Italian Prime Minister Giuseppe Conte said of Mr Timmermans’s chances when briefly descending from the meeting room at EU headquarters at around breakfast time.

The Timmermans option has deeply divided the European People’s Party (EPP) as it would surrender the key post to the rival Socialists and Democrats (S&D) bloc despite the EPP remaining the biggest group in the EU following last month’s election.

Bulgarian Prime Minister Boyko Borissov, an EPP stalwart, posted a video on his Facebook account of a discussion with Mr Timmermans in which Mr Borissov said the Dutchman should get the commission job while the less coveted parliament presidency should go to EPP candidate Manfred Weber.

But Irish Prime Minister Leo Varadkar insisted that the “vast majority of the EPP prime ministers don’t believe we should give up the presidency of the commission quite so easily, without a fight”.

A journalist rests during the late-night negotiating session in Brussels Credit: Virginia Mayo/AP

After negotiations started early on Sunday, summit host and EU Council president Donald Tusk had more than 30 bilateral meetings in his attempt to find a breakthrough.

The appointments must take into account political affiliation, geography – balancing east and west, north and south – population size and gender.

The leaders of EU institutions are supposed to impartially represent the interests of all member nations globally and in Brussels.

Some leaders discussed the roster of upcoming vacancies, which also include the EU’s top diplomat, the president of the European Parliament and the chief of the European Central Bank (ECB), on the sidelines of the Group of 20 summit in Japan that concluded on Saturday.

Mr Tusk wants nominations to be wrapped up soon, seeking to prevent further erosion of public confidence in the EU amid Brexit uncertainty and intra-bloc divisions over managing migration.

European Council president Donald Tusk, left, with Renew Europe party member Guy Verhofstadt Credit: Virginia Mayo/AP

There was hope at the previous summit on June 20-21 that more time would clarify who should replace Mr Juncker.

German Chancellor Angela Merkel backs Mr Weber, the German conservative whose centre-right EPP is the largest political group in the European Parliament but lost seats in the EU elections in May.

French President Emmanuel Macron has suggested Mr Weber lacks the political and government experience for such a high-profile role.

Mr Weber could still be considered for the head of the European Parliament, which is the EU’s only elected institution.

Mrs Merkel said there was still a good possibility for Mr Weber and Mr Timmermans, the top centre-left candidate from the S&D group, to be among the winners of the top positions.

German Chancellor Angela Merkel arrives for the EU summit Credit: Olivier Matthys/AP

Other leaders from the same political family disagreed.

The EPP and the S&D are the two biggest political groups in the EU, but both lost seats in May’s polls, where far-right and populist parties, pro-business liberals and the Greens made gains.

EU leaders want to fill the positions soon because the European Parliament is set to pick a new president next Wednesday.

Under EU rules, member countries choose who will run the commission, replacing Mr Juncker.

The parliament must endorse that choice.

But the assembly has insisted that only the lead candidates from parties that ran in last month’s elections should be eligible for the post.

“The lead candidates is not the only criteria,” said Mr Conte.

The commission proposes and enforces EU laws on policies ranging from the massive single market to agriculture spending, and from competition issues to immigration.

European Commission president Jean-Claude Juncker Credit: Francois Lenoir/AP

The job responsibilities are huge: Mr Tusk and Mr Juncker negotiate with the likes of US President Donald Trump and Chinese leader Xi Jinping, while the head of the ECB can set monetary policy for the 19 nations that use the shared euro currency.

The outgoing group of EU officials was lopsidedly Italian, with Antonio Tajani holding the parliament top post, Mario Draghi head of the ECB and Federica Mogherini the EU foreign policy chief.

Top candidates include current prime ministers Stefan Lofven of Sweden and Andrej Plenkovic of Croatia.

Others mentioned include Brexit negotiator Michel Barnier of France, Greens leader Ska Keller of Germany, Lithuanian President Dalia Grybauskaite and Margrethe Vestager, the EU’s competition chief since 2014.

On Monday a spokesman for Mr Tusk said the summit had been suspended and would reconvene on Tuesday morning.