European Commission chief Jean-Claude Juncker on Sunday called for the creation of an EU army in the wake of rising tensions with Russia.
Juncker said the force could help counter new threats beyond the bloc's borders and defend European "values", in an interview with Germany's Welt am Sonntag newspaper.
"You would not create a European army to use it immediately," he was quoted as saying.
"But a common army among the Europeans would convey to Russia that we are serious about defending the values of the European Union."
He said a joint EU force would also lead to more efficient spending on military equipment and drive further integration of the bloc's 28 member states.
"Such an army would help us design a common foreign and security policy," the former Luxembourg prime minister said, but added that the force should not challenge NATO's defence role.
"Europe's image has suffered dramatically and also in terms of foreign policy, we don't seem to be taken entirely seriously."
The proposal was likely to rile opponents of deeper EU integration such as Britain but has won some support from Germany.
Defence Minister Ursula von der Leyen said last month that she was confident that "perhaps not my children but my grandchildren will have a United States of Europe" with its own military, news agency DPA reported.
Welt am Sonntag quoted the head of the German parliament's foreign policy committee, Norbert Roettgen, as saying that an EU army "is a European vision whose time has come".
The newspaper said that former NATO Secretary General Javier Solana would present a report on Monday in Brussels entitled "More Union in European Defence" calling for a new European security strategy including military capability to intervene beyond EU borders.