Brussels - Herman Van Rompuy entered the race for the post of European Union chief as favourite Thursday as leaders headed for Brussels to pick their first-ever, full-time president.

Preparations were already underway for the possible departure of Belgium's prime minister, with the Belgian media speculating about likely post-Van Rompuy scenarios.

"It's D-Day for Van Rompuy and Europe," read the front-page headline of the daily Le Soir along with articles suggesting the possible return to power of his predecessor, Yves Leterme.

Van Rompuy's unofficial candidacy was strengthened on Wednesday when German Chancellor Angela Merkel said she planned to strike a deal on names with the EU's other powerbroker, French President Nicolas Sarkozy.

Germany and France are both believed to be in favour of a candidate from a smaller member state. Van Rompuy has won favours in Paris and Berlin by supporting their opposition to Turkey becoming an EU member.

While Germany has not explicitly backed any candidate, its ambassador to Belgium, Reinhard Bettzuege, was quoted by Belgian paper De Morgen as saying Germany favoured Van Rompuy, a comment that was subsequently denied in Berlin.

Moreover, the Belgian's election faces opposition from other major EU players, with Swedish Prime Minister Fredrik Reinfeldt conceding that no consensus candidate had emerged out of his pre-summit consultations with fellow leaders.

Sweden currently holds the EU's rotating presidency.

Britain, for instance, is continuing to promote the candidacy of former premier Tony Blair, and the country's media has already mounted a vicious attack on Van Rompuy's federalist agenda.

Italy has also backed Blair in the past.

The election will be decided by qualified majority, with the winning candidate needing at least 255 out of 345 votes available. He or she will also need the support of at least two-thirds of the bloc's 27 member states.

Germany, France, Italy and Britain all have 29 votes each at their disposal, with Poland and Spain commanding a further 27 votes each.

Meanwhile, former Italian premier Massimo D'Alema, a social democrat, is seen as a frontrunner for the other major post being created by the Lisbon Treaty, that of foreign policy chief.

D'Alema enjoys the backing of conservative Prime Minister Silvio Berlusconi, but is viewed with suspicion by Poland and other Eastern states because of his communist origins.

Spain is also promoting its own candidate for the post, Foreign Minister Miguel Angel Moratinos.

However, Moratinos' chances are seen as slim, given that the foreign policy chief would also assume the vice-presidency of the European Commission, which is currently headed by another Iberian, Jose Manuel Barroso of Portugal.

The third post up for grabs at Thursday evening's summit is that of secretary general of the council.

Reinfeldt has warned delegates to brace themselves for possible all-night discussions in Brussels. (dpa)