An overwhelming majority of Danes have voted in favor of joining the EU's common defense policy 30 years after opting out, unofficial results of a referendum on June 1 show.
With 97 percent of the ballots counted, about 67 percent voted for scrapping the opt-out.
"Tonight Denmark has sent a very important signal. To our allies in Europe and NATO, and to [Russian President Vladimir] Putin. We're showing, that when Putin invades a free country and threatens the stability in Europe, we others pull together," Danish Prime Minister Mette Frederiksen told cheering supporters.
European Commission President Ursula von der Leyen and European Council President Charles Michel welcomed Denmark's "historic choice."
Denmark's decision is a "strong message of commitment to our common security," von der Leyen said on Twitter.
"I am convinced that both Denmark and the EU will benefit from this decision," she said.
The referendum, which came shortly after Sweden and Finland applied to join NATO, is the latest security move by a European country in response to Russia’s invasion of Ukraine.
SEE ALSO: The View From Finland: 'The Russian Garrisons Have Been Emptied. They Don't Have Anything'Some 4.2 million Danish voters were eligible to cast ballots in the referendum.
Denmark is a founding member of NATO and joining the EU's defense policy will have a relatively modest impact on Europe’s security architecture.
The main change will be that Danish forces will be able to take part in EU military operations such as those in Africa and Bosnia, and Danish officials will be able to stay in the room when EU colleagues discuss defense topics.
Copenhagen has been reluctant to join the EU's efforts to build a common security and defense policy in parallel with the transatlantic NATO alliance.
It was one of the opt-outs that Danes insisted on before adopting the EU’s founding document, the 1992 Maastricht Treaty, which laid the foundation for political and economic union. Among the other important ones were cooperation in EU justice and home affairs and adopting the common currency -- the euro.
In a referendum in 2000, Danish voters reinforced their decision to snub the eurozone, and 15 years later they voted to keep the exemption on justice and home affairs.