Presenting the declaration after the summit, Slovenia's President Borut Pahor said that the initiative aimed not only to bridge the gaps between participating countries but also in the EU and strengthened transatlantic relations.

As a platform at presidential level, the initiative is an opportunity to create an equally strong voice in the EU for the participating countries and strengthens the democratic legitimacy of the EU.

Bringing together 12 countries situated between the Baltic, Adriatic and the Black Sea, the initiative aims to improve the competitive edge of member states and improve the life of its people with concrete projects, Croatian President Kolinda Grabar Kitarović said.

To realise the projects, the initiative has established its own fund. While today no concrete figures were revealed about the Three Seas Fund, declared functional yesterday at the business forum accompanying the summit, it was said that the European Investment Bank had promised its support for the fund today.

According to a report by German news portal DW, the fund was established only days ago and has a balance of around EUR 500 million with the goal to reach EUR 4-5 billion.

Also present was the outgoing president of the European Commission, Jean Claude Juncker, who praised the initiative for its concrete projects, and also illustrated with figures how much the EU has already invested and will continue to invest in the region.

"Between 2014-2020, we have invested from the structural fund EUR 60 billion in this region. The Juncker plan has generated in these years EUR 42 billion for the 12 member states of the region. I believe that we have done and will do everything to support the efforts aiming at better cohesion and better connectivity in the region."

For the next financial perspective, 2022-2027, the Commission has foreseen EUR 42.3 billion to improve the interconnectivity in Europe and in particular in this region, said Juncker.

The press conference was also addressed by presidents of Romania and Poland, Klaus Werner Iohannis and Andrzej Duda, with the latter saying that the next summit of the initiative would take place in Estonia, where the presidents had been invited by President Kersti Kaljulaid.

The presidents expressed in their statements, as well as the declaration, an invitation to other potential partners, encouraging "the inclusion of actors from the Three Seas Initiative member states and the US to the existing network".

They were especially pleased that the two-day event hosted by Slovenia was attended not only by Juncker but also German President Frank-Walter Steinmeier, as well as US Secretary of Energy Reick Perry. The latter took part in the presidential panel hosted by Pahor as part of an accompanying business forum yesterday, inviting participants to buy US gas.