NATO criticised Balkan countries on Thursday for not helping to bring indicted war criminals to justice and called on them to live up to their international obligations. NATO chief Jaap de Hoop Scheffer also urged Kosovo Albanians to remain calm in the event that the United Nations war crimes tribunal decided to indict Kosovo's newly elected Prime Minister Rasmush Haradinaj for war crimes. Foreign ministers from the alliance called on Bosnia, Serbia and Montenegro, and Croatia to improve cooperation with the tribunal and its chief prosecutor Carla del Ponte. In all three cases, progress towards membership of the European Union and NATO -- declared goals of Zagreb, Sarajevo and Belgrade -- hinges on displaying a commitment to upholding international law by complying with the U.N. court. Last month, del Ponte said Serbia's lack of cooperation with The Hague was "the single most important obstacle" to the court completing its work, and singled out the Serb half of Bosnia for failing to arrest a single war crimes suspect. --More 2135 Local Time 1835 GMT