German defence minister Ursula von der Leyen has warned the UK against getting involved in EU security matters.
"The plea to the British is only not to block important European developments, when they say they want Brexit," von der Leyen told the Financial Times.
"It is not good to prevent Europe from organising itself better."
Read more: Britain to veto establishment of an EU army
The comments from von der Leyen came weeks after Britain's defence secretary Michael Fallon said the UK would block the formation of an EU army.
The plan to create an EU army has been formed by France and Germany. The two nations have put together a timetable for establishing a force that would rival Nato.
Last month, a document on the EU army was discussed at a summit in Bratislava that Britain did not attend. The European Commission is set to make proposals on the military force in December, aiming to get an agreement by June next year.
But Fallon told The Times the EU army is "not going to happen".
We are full members of the EU and we will go on resisting any attempt to set up a rival to Nato.
We have always been concerned about unnecessarily duplicating what we already have in Nato.
However, von der Leyen denied the Germans are trying to create a European army.
She said: "The UK has signalled that it is sceptical, so it is important to explain what this is about. It is not about a European army but about the fact that we Europeans expand our security and defence policy and so work together better, especially in complex crises in non-Nato regions, as in Africa."
Germany has become more activist in international affairs in recent years, but has traditionally taken a more passive stance due to the country's Nazi past. An EU army would be a vehicle through which the Germans could act abroad more easily.