Croatia introduced the euro on Sunday, expanding the single-currency bloc to 20 countries. The country is scheduled to transfer from the kuna over the next two weeks.

Croatia became the first nation to adopt the euro since Lithuania in 2015. The shared currency was launched in 1999 with 11 members, including Germany and France.

Croatia also joined the Schengen zone, which allows free movement of people and goods mainly among European Union states.

The question is whether the move will help strengthen the unity of the EU.

Conflict is deepening between the EU and Russia amid Moscow's invasion of Ukraine, while Hungary, an EU member, has shown a pro-Russian stance.

But more member states may seek eurozone membership to boost their economic security. Bulgaria, another EU nation, is aiming to introduce the currency from 2024.