The event in the Serbian capital was organised by NATO's Supreme Allied Commander Transformation (SACT), and it brought together delegations from some 60 countries, including Croatia.
The conference focused on strategic matters of common interest, joint training, partnership, global resources and development of the armed forces.
Di Paola said at a news conference that he was satisfied with the new direction in relations between Serbia and the alliance.
We respect every partner's right to choose the level of their engagement. In that sense we regard Serbia as a very significant partner and we are looking forward to the intensification of that cooperation in the manner that suits Serbia, the NATO official said.
He said that NATO was interested in a stable and developed Western Balkans and that it was optimistic about the future of alliances.
General Miletic said the conference provided a good opportunity for Serbia to strengthen its military cooperation with a number of countries.
"They fully accept our position on military neutrality," Miletic said, adding that the level and modalities of cooperation with NATO were matters to be decided by Serbia.