"The day after tomorrow, Croatia will become a member of the European Union. The European Union will then have 28 member states and we are looking forward to the new member," Merkel said.

She recalled that Croatia began the accession process in 2004, when "strenuous, years-long negotiations began... Croatia had to change. The opening of each chapter meant the need to implement new reforms."

"I congratulate Croatia on crossing that path together with us and on the fact that we can now welcome Croatia as a new member," Merkel said, adding that accession did not mean that "political work" had ended. "In the area of legal security and fight against corruption, additional steps need to be taken," she said, pointing to the need to carry on with reforms in the economy and the labour market.

"But that doesn't apply only to the new member Croatia, it applies to us all. Because Europe lives in a changing world and we must always show anew that we are competitive and that we can export our products so that our countries can create new jobs."

Markel recalled that Croatia was in the region of the former Yugoslavia and that it was the second EU member country from there. "This means that we keep our word. We said that all Western Balkan countries have the prospect of European Union accession. Croatia's example also shows that this path is long, because 2004-2013 is a long period of time."

The chancellor also spoke of the Croats in Germany in the context of Croatia's EU accession. "I am happy about the 220,000 Croats who live in Germany because now they will have many benefits. The EU not only has another four million citizens who live in Croatia, but Croats in Germany too will now be able to participate in communal and European elections and have many administrative benefits."

"All in all, welcome to the European Union, Croatia!" Merkel said in her video message.