t was Defence Minister Andreja Katič and Foreign Minister Karl Erjavec who signed a notification of Slovenia's intention to join the Permanent Structured Cooperation on security and defence (PESCO).

The cooperation, enabled under the Lisbon Treaty, allows the countries to cooperate more closely on building up defence capabilities.

The "historic" step was also hailed by German Foreign Minister Sigmar Gabriel who said this milestone in European defence would also bring economic benefits.

The new permanent form of defence cooperation evolved from the French-German initiative of autumn 2015, said French Foreign Minister Jean-Yves Le Drian, who said Europe was enhancing its defence also in response to terrorism.

Based on a proposal by Germany, France, Spain and Italy, the document entails some 20 commitments in five areas the member states pledge to meet by 2025.

These areas are investment, capability planning, interoperability, capability availability, flexibility and deployment of forces, cooperation to make up for deficient capabilities and programmes for equipment.

The EU is to establish the new permanent form of defence cooperation on 11 December, by which time the member states are to have prepared their national plans for implementing the project.