Czech Prime Minister Bohuslav Sobotka has reignited calls for the formation of an EU army, with the bloc facing threats from revanchist Russia and infiltration by Islamist militants.

Sobotka told a meeting of Czech diplomats in Prague: "In the face of uncontrolled mass migration, even states in the centre of Europe have realised that internal borders must be better controlled. Aside from better co-ordinated foreign and security policy, I also believe that in the long term we will be unable to do without a joint European army."

A common army should not compete with Nato but should make the EU a "more reliable partner", he added.

Britain opposed the formation of a European Army, backing Nato as the chief guarantor of European security. However Britain's exit from the Union – and a range of security threats – have prompted European officials to renew calls for closer military integration.

It comes as Germany raised the possibility of re-introducing conscription, as one of a series of measures considered in the face of a threat.

Sobotka said that EU leaders may discuss plans for a European Army in September. "I hope that the autumn European summit will bring concrete proposals and pledges," he said.

In 2015, EU Commission President Jean Claude Juncker said he backed plans for the formation of an EU army.

In a review of EU security policy published in June, foreign policy chief Federica Mogherini said that the bloc must develop the capacity to act unilaterally in the face of threats "if and when necessary."