Both countries are strong advocates that NATO should put enlargement to the Western Balkans on the agenda of its summit in Wales in autumn, the ministers told the press.

"The policy of open doors is urgent...Montenegro is the best prepared of the four candidates for membership. It is crucial in terms of stabilisation of Western Balkans," Jakič said.

The pair discussed the strengthening of bilateral defence and military cooperation just weeks after the armies held a joint surface-to-air firing exercise in Istria.

"We're very pleased with the realisation of existing activities...We also signed an agreement for next year that involves 32 joint activities," said Jakič.

Kotromanović noted that Slovenia and Croatia had the most intense bilateral cooperation in NATO after the US, Germany and Poland. "We decided today that continuing and strengthening cooperation is strategically important."

Aside from holding joint exercises, Slovenia and Croatia plan to cooperate in officer training, as Slovenia will send one officer to the Croatian military academy in autumn.

The ministers also highlighted cooperation in civil protection; Croatia was the first to help out with emergency power generators in the January ice storm while Slovenia supplied sandbags for flood defences around Karlovac in spring.

Minister Jakič wrapped up his first official visit to Croatia by meeting President Ivo Josipović, Foreign Minister Vesna Pusić and members of the Croatian parliament.

Talks with members of the parliamentary Defence Committee revolved around cooperation in defence as well as the impact budget cuts had on defence capabilities of both countries.

Pusić and Jakič meanwhile decided to launch a joint initiative to secure an invitation to NATO for Montenegro at the alliance's autumn summit.

Jakič told the STA that Slovenia and Croatia will send a joint letter to member countries about the importance of Montenegro's membership in NATO in regards to the stability of the region.

Talks with Croatia's president meanwhile revolved around Slovenia's experience with airspace control within the NATO framework, as Slovenian air is policed by Italian and Hungarian pilots.