The EU is not going to get an army of its own in the near future but in the meantime it should play a greater security role, EU foreign affairs chief Federica Mogherini said Friday.

"We all agree that the European army is not something that is going to happen any time soon," Mogherini said after an informal meeting of the 28 European Union foreign ministers in Bratislava.

"But what can happen very soon, if member states are committed, is to advance in the field of European defence and that is what I put on the table today," she said.

Member states, led by Britain, agree with the principle of increased defence cooperation but baulk at the idea of giving up the crucial sovereign right to decide their own security policy.

However, a growing list of security challenges, from the migrant crisis to international terror, have emboldened the EU's executive arm, the European Commission, and Mogherini to push the idea forward.

"Fifty, 60, 100 years from now, who knows?," Mogherini told a briefing when asked about the possibility of a "European Army."

"The important thing is that all the ministers appreciated the plans... now is the time for real stuff and this is only the beginning," she added.

Earlier this year Mogherini unveiled a "Global Strategy for Foreign and Security Policy," winning approval from EU leaders to develop her plan.

Mogherini said Friday that the foreign ministers were unanimous in backing the concept and she would now work on concrete proposals to put it into effect, suggesting the first operational results could be seen early next year.

British foreign minister Boris Johnson -- who campaigned for Brexit -- attended the meeting in Bratislava and said earlier that Britain remained committed to defence cooperation with the EU even though it had voted to leave the bloc.

Britain is an important, nuclear armed military power, plus it holds a veto as a permanent member of the UN Security Council.

Its shock June vote to quit the EU stoked intense speculation that the other member states might now press ahead with the type of joint defence initiative London had stymied.

EU leaders and top officials have recently stressed the possible role the bloc could play in ensuring security for its citizens in a dangerous world.