Truss' advisers have also offered to host the forum's next summit in Britain, an EU diplomatic source said.

Politico, which first reported Truss' attendance at the summit, said the meeting will focus on the Ukraine conflict and energy security.

French President Emmanuel Macron had first proposed the idea of a European Political Community in an effort to counter Russian and Chinese influence in the Balkans and Eastern Europe.

The idea was also to ensure countries like Britain, Norway and Switzerland have a political forum to collaborate with the European Union and work on common projects, such as immigration or energy.

Some countries, however, have expressed scepticism, fearing the new grouping could be a way to keep candidates to EU membership outside the club, while others have criticised it as a new talking shop without a clear purpose.