NATO builds relationships with partners through military-to-military cooperation on training, exercises, disaster planning and response, science and environmental issues, professionalization, policy planning, and relations with civilian government.
Thirteen former member states of the PfP (namely Albania, Bulgaria, Croatia, Czech Republic, Estonia, Hungary, Latvia, Lithuania, Montenegro, Poland, Romania, Slovakia, and Slovenia), have subsequently joined NATO. On April 26, 1995 Malta became a member of PfP; it left on October 27, 1996 in order to maintain its neutrality. On March 20, 2008 Malta decided to reactivate their PfP membership; this was accepted by NATO at the summit in Bucharest on April 3, 2008. During the NATO summit in Riga on November 29, 2006, Bosnia and Herzegovina, Montenegro, and Serbia were invited to join PfP, which they did on December 14, 2006.