Cerar, speaking to the press after meeting Juncker, said the bloc was looking at a year of intense talks on how to move forward, a period which he said was "the hour of truth" for the bloc.

The Commission laid out five scenarios ranging from loose cooperation revolving around the single market, various degrees of a multi-speed Europe to a federal system.

Neither the Commission nor Slovenia have expressed preference for any of the possible scenarios.

Juncker told the press at Brdo pri Kranju that "for once [the Commission] is not imposing, dictating, prescribing, we are submitting to the meditation of member states five scenarios."

"We would like to see huge debate, I count on Slovenia to be part of this debate, to inspire this debate...to bring the debate to a level which can inspire big member states."

Whereas Cerar described both Juncker and himself as "convinced Europeans", Juncker emphasised he was "a federalist when I was 15".

"Now I think the EU can be constructive not against nations and member states but together with nations and member states, which is important in particular for small member states," he said, noting that this was particularly important for small member states.

Cerar meanwhile stressed that the bloc needed to focus for the time being on implementing existing agreements in order to show the people that the EU can be not only efficient but also friendly to its inhabitants.

Accordingly, the EU needs to tackle migrations and security; without addressing these two issues it will be unable to focus on key aspects of its future development.

In the long term, however, "it is necessary to be ambitious". The long-term vision needs to take shape through broad debates that have to involve the civil society, intellectuals and the parliament, Cerar said at the joint news conference.

Juncker also praised Cerar, who he said "started as a nobody" but "quickly became somebody", building up a reputation in a very short period of time. He described him as being influential in the European Council and the EU in general.

He likewise praised Slovenia for "behaving like a founding member", a country strongly committed to integration that is influential and "a positive actor in the EU".

This was Juncker's first visit to Slovenia after 2008, when Slovenia was presiding over the EU, and his first in his capacity as Commission president.