European Parliament President Antonio Tajani says the legislature believes the new head of the EU executive Commission should be chosen from the candidates put forward by the political groupings in the parliament.

That could put the legislature at odds with some EU leaders who want a wider choice in the search for a successor to Jean-Claude Juncker.

According to the rules, the EU leaders have to take the election results into account to select a new EU Commission president, but they do not have to choose any of the blocs' candidates.

The European parliament however, will have to approve the new president, and this could lead to a long session of horse trading between the legislators and the EU leaders.

Over the next months, the EU also has to pick new leaders for the EU Council, the parliament, the European Central Bank and a foreign policy chief. Traditionally the choices for those spots are always interrelated and subject to hot debate among the political groups.