(AP-ANSA) - PRISTINA - Kosovo's president says the decision to transform the country's security force into an army is "irreversible" but assures neighboring Serbia it doesn't have to worry about ethnic Serbs living in Kosovo. President Hashim Thaci held a briefing on Sunday before leaving for New York, where the United Nations Security Council is expected in coming days to discuss the small Balkan country's decision. Kosovo's parliament overwhelmingly approved the army's formation on Friday. Serbia has warned that an army in its former province could result in an armed intervention. Serbia does not recognize Kosovo's 2008 declaration of independence. Its government insists the new army violates a U.N. resolution that ended Serbia's crackdown on Kosovar separatists in 1998-1999. Any Serbian armed intervention Kosovo would mean a direct confrontation with the NATO-led peacekeepers stationed in Kosovo since 1999. (AP-ANSA).