PRAGUE - The European Union wants the 44 countries gathering for an inaugural summit in Prague of the European Political Community (EPC) on Thursday to highlight Russia's international isolation over Moscow's war in Ukraine, the bloc's top diplomat said.

However, the summit will likely be dominated by differences about how to cap gas prices to contain soaring energy costs driven by the war that are taking the air out of the post-COVID economic recovery.

A brainchild of French President Emmanuel Macron, the EPC brings together the 27 member states of the European Union and 17 other countries, including several waiting to join the bloc and the only one ever to leave it, the United Kingdom.

"This meeting is a way of looking for a new order without Russia. It doesn't mean we want to exclude Russia forever, but this Russia, Putin's Russia, does not have a seat," he said.

Borrell stressed the EPC gathering included countries from Britain to Serbia to Turkey, stretching from the Caucasus to the North Sea and the Mediterranean.

"This is the signal that we want to send, that unhappily we cannot build a security order with Russia. Russia is isolated... You don't have a seat, all others are here."

The gathering at the sprawling Prague Castle is seen as a grand show of solidarity for a continent mired in multiple crises - including the security and economic consequences of the war in Ukraine. The organizers, however, have been unclear about the forum's concrete goals.

Borrell had said on the eve of the summit that the many leaders would meet for just half a day for an "initial exchange." Questions about the forum's ultimate purpose, membership and functioning remain unresolved, he said.

Some have already written off the EPC as just another talking shop, one that will be difficult to manage not just because of its size but also because of its diversity and the traditional rivalries between many of its members, from Armenia and Azerbaijan to Greece and Turkey.

Others saw a hope in British Prime Minister Liz Truss's decision to attend, a gesture possibly opening the way for warmer ties between the EU and London that have been frayed by post-Brexit wrangling over Northern Ireland.

Among the 27, tensions will also play out over Germany's 200 billion euro ($197.50 billion) support package for businesses and households that many other member states criticise for damaging competition on the EU's single market.

Prague Castle is a sprawling complex founded more than a 1,000 years ago that includes a cathedral and cobblestone streets, will be followed on Friday by a meeting of EU leaders.

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(Reporting by Sabine Siebold, Michel Rose, RObert Muller, Jan Lopatka in Prague, Philip Blenkinsop in Brussels; Writing by John Chalmers and Gabriela Baczynska; Editing by Josie Kao and Frank Jack Daniel)