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RIGA (Reuters) -NATO's eastern flank leaders will have a more coordinated approach towards supporting Ukraine after the Hungarian president stayed away from their summit in Riga, Latvian President Edgars Rinkevics said on Tuesday.

The split emphasizes diverging approaches to Russia and Ukraine among central European nations, amid Hungarian Prime Minister Viktor Orban's continued close ties to Russia and refusal to give arms to Ukraine.

Rinkevics said Hungary's President Tamas Sulyok cancelled his trip to the summit of the Bucharest Nine, a group of European countries on the eastern edge of NATO, at the weekend.

"The most important thing is that we have a more coordinated approach to the (NATO) Washington summit, when it comes to support for Ukraine, when it comes to strengthening the alliance's capabilities", Rinkevics said ahead of the meeting.

Sulyok's office did not respond to a request for comment.

Slovak President Zuzana Caputova called off her trip to Riga "at the last minute", the Latvian president's office said.

Slovakia stopped state military aid to Ukraine when Prime Minister Robert Fico's government took power last year.

The Slovak foreign ministry told Reuters Caputova's term in office was ending this week, and Fico was unable to attend as he was recovering from an assassination attempt in May.

NATO Secretary General Jens Stoltenberg, Finnish President Alexander Stubb and Swedish Prime Minister Ulf Kristersson also attended Tuesday's event, which comes ahead of a NATO leaders meeting in Washington in July.

"I'm confident that NATO allies will agree at the NATO summit", Stoltenberg told reporters, declining to comment on the absentee countries.

Stoltenberg will visit Budapest on Wednesday.

The Bucharest Nine includes Bulgaria, the Czech Republic, Estonia, Hungary, Latvia, Lithuania, Poland, Romania and Slovakia.

(Reporting by Andrius Sytas in Vilnius and Janis Laizans in Riga; additional reporting by Jason Hovet in Prague. Editing by Bernadette Baum)

By Andrius Sytas and Janis Laizans