"Slovenia ranks in the lower part of countries in terms of percentage of GDP it allocates for defence. The important guideline of the summit for us, apart form smart defence and other activities related to rationalisation, is to take into account the current economic situation," Janša said.

Noting that Slovenia's economy was likely faring worse than the average of the member states, Janša said: "It is important not to insist on 2% of GDP as percentage earmarked for defence at all cost."

"The summit will turn out to be more important than it seemed at first. Two dimensions are crucial. The first concerns NATO reorganisation at a time when most of the developed world is going through an economic crisis, and several decisions focus on how to provide the same or higher level of defence with less money."

The summit focused on Afghanistan, where Janša said the operation by NATO and partner countries could serve as a model for other international interventions. However, he stressed that it should be made sure that the effort invested so far is not in vain.

"This is an operation that has an uncontested legal basis in UN resolutions and where 22 other countries that are not members of NATO are taking part. The important thing is to secure sufficient financial means for the progress in Afghanistan to last," Janša told Slovenian reporters in Chicago.

NATO leaders endorsed the decision to withdraw combat troops by the end of 2014. "Then the period of building stability will set in and various international organisations and countries will keep their presence," Janša said.

He stressed that Slovenia would contribute its share to boosting democratic standards, transparency and economic development.

Moreover, Slovenia was among the countries that insisted that the summit make a decisive commitment to open-doors policy.

"We find it vital for the prospect of full membership to be kept open for the candidate countries in line with the guidelines of the previous summits," said Janša, adding that disputes such as the name row between Macedonia and Greece had nothing to do with membership criteria.

"Everyone aware of the significance of the policy of open doors will have to put more effort to ensure that it will not be forgotten in this phase of NATO's transformation from a regional into global power," the Slovenian PM said, adding that partnership was not equal to full-fledged membership.