Altenburg said this at his meeting with the chairman of the Croatian parliamentary foreign affairs committee, Gordan Jandrokovic, and the head of the Sabor delegation to NATO's Parliamentary Assembly, Kresimir Cosic, the Sabor public relations office said in a statement.
The NATO official said Croatia was making evident headway towards full membership in the Alliance and that in recent years it had made impressive progress in the implementation of many reforms, as well as in meeting political criteria for the membership.
The key issue, however, is the case of the runaway general Gotovina and NATO is expecting its resolution as soon as possible. The responsibility for this lies only with Croatia, Altenburg was quoted in the statement as saying.
Cosic said that his country was absolutely aware that its fulfilment of all political criteria was necessary for its admission to Euro-Atlantic institutions and it was doing its utmost to solve the last remaining outstanding issue in relations with the Hague-based tribunal.
Jandrokovic said that efforts which Croatia was making should be recognised by the international community not only because of Croatia but also because of its neighbouring countries and the stabilisation and progress of the entire region.
According to the statement, Altenburg praised Croatia for its support to NATO operations in Bosnia-Herzegovina and Kosovo and for its engagement in the ISAF peace mission in Afghanistan.
Croatia will continue to enjoy the Alliance's support in its active participation in the Membership Action Plan (MAP) until the completion of reforms and the country's admission to NATO, he added.
On Wednesday, Altenburg also held talks with Croatian Defence and Foreign Ministers Berislav Roncevic and Kolinda Grabar Kitarovic respectively, and was received by Prime Minister Ivo Sanader and President Stjepan Mesic.
During his talks with Mesic, the Croatian head of state informed him of good results in the downsizing of the military and the restructuring of the defence forces as part of the country's efforts to join NATO.
Mesic spoke about two main Croatian strategic goals: entry into the European Union and NATO, stressing that the country was making many efforts in many areas so as to accomplish those objectives, the Office of the President said in a press release.
A delegation of NATO's Planning and Review Process and Membership Action Plan (PARP/MAP) started a review of partnership goals taken over by Zagreb at the Croatian Defence Ministry on Monday. This is a regular inspection of Croatia's progress in fulfilling partnership goals and implementing the Annual National Programme,