Talks between EU leaders to appoint the next team of top officials will continue on Tuesday, with former Dutch foreign minister Frans Timmermans still hoping to replace Jean-Claude Juncker as president of the European Commission.

Timmermans, 58, is the ‘Spitzenkandidat’ or leading nominee for the centre-left socialist group in the European Parliament, which finished second in the recent European elections.

His chief rival for the post is Germany’s Manfred Weber, who represents the centre-right European People’s Party (EPP) dominated by conservative and Christian Democrat factions.

Although the EPP won more seats in parliament, there is speculation Weber could be offered a different post because Timmermans is the more popular of the two with Europe’s third political ‘family’, the liberal group, which was one of the main winners in May.

The distribution of Europe’s top posts, including the presidency of the commission and the European Council, currently headed by Donald Tusk, and the chair of the European Parliament, will need to reflect the geographical and political make-up of the EU as well as a fair balance of men and women.

The talks began on Sunday evening and continued for most of the night. They broke up at lunchtime on Monday without agreement after passing the 18-hour mark, making it the longest summit since the EU expanded to 28 nations. The leaders will reconvene at 11am on Tuesday.

Timmermans, currently the first vice-president of the commission, has the support of German chancellor Angela Merkel, although French president Emmanuel Macron said last month that neither of the two main Spitzenkandidaten were fit for the job.

His main opposition comes from Eastern European nations, where leaders such as Hungary’s Victor Orban have been angered by his criticism of their attitude to the rule of law. Italy’s populist-led government is also known to be sceptical of Timmermans, while Croatia and Ireland argue the Socialists should not be given the job after finishing second in the election.

Prime minister Mark Rutte was tight-lipped about Timmermans’s chances as he arrived at the summit in Brussels on Sunday. ‘It’s a moving picture,’ he said. ‘Things will shift.’

Timmermans was credited with being one of the main reasons for the Labour party’s (PvdA) unexpectedly strong performance in the European elections. It finished top of the poll only two years after a disastrous showing in the general election when the party lost three-quarters of its seats.

Timmermans himself was cautious about his prospects when asked on Sunday. ‘There will be a long discussion among the leaders this evening. ‘You hear all sorts of things, but I can’t make any assumptions yet.’