It's first day as a European Union member, Croatia has pledged to help other Balkan countries move closer to the bloc and to help bring lasting stability to a region which was engulfed in conflict 20 years ago.

Croatian president Ivo Josipovic met Monday with the leaders of other Balkan countries, just hours after Croatia became the union's 28th member state. It is only the second former Yugoslav republic to join, following Slovenia in 2004.

Josipovic says Balkan leaders have agreed to meet in the future and try to agree on joint projects and resolve remaining issues weighing on regional ties. He said, "I look at the future with much optimism."

Montenegro is expected to be the next in line to join the EU.