The leaders of Kosovo and Serbia have faced off at the United Nations Security Council, days after Kosovo voted to transform its lightly armed security force into a full-fledged army.
Kosovo's move has angered Kosovo's ethnic Serbs as well as Belgrade, and also prompted warnings from NATO.
President Hashim Thaci said at the United Nations on December 17 that it was a "natural step" to establish an army to cement Kosovo's status as a sovereign nation.
"If Kosovo made a mistake, it's only that we waited for five years to establish an army," Thaci said.
Kosovo was a province in Serbia until 1999, when NATO launched air strikes to stop the killing and expulsion of ethnic Albanians by Serbian forces during a two-year war. Nearly two decades later, the landlocked territory of 1.8 million people is still guarded by NATO troops.
Kosovo declared independence from Serbia in 2008. Although more than 110 countries recognize Kosovo, Serbia does not.
Serbian President Aleksandar Vucic, however, called on the world body to "curb" and "tame" Kosovo. Vucic also dismissed the "so-called sovereign right" of Kosovo to form its own military.
Vucic said he was "very much worried, very much concerned and even a bit afraid" about the implications of a Kosovar army.
The December 14 vote by Kosovo's parliament aimed at converting its 2,500-member Kosovo Security Force into a national army with some 5,000 personnel and more substantial weaponry. The vote was boycotted by political parties dominated by ethnic Serbs, who number around 120,000 in Kosovo.
Some leaders in Belgrade have suggested that Serbia could use its own military to respond to the "ethnic cleansing" of Serbs.
The United States has expressed support for Kosovo's move to create a national army, while NATO said the move was "ill-timed."
UN Secretary-General Antonio Guterres, meanwhile, expressed concern over Kosovo's plans, saying in a statement that any restriction to the security responsibilities of the NATO-led peacekeeping mission would be inconsistent with the UN Security Council resolution that set up the mission.
Russia has been vehemently opposed to the Kosovo move. Ambassador Vasily Nebenzya said expanding the army was a "blatant violation" of Security Council resolutions and called the creation of the army "illegal."
Both Kosovo and Serbia have been told they must resolve their differences in order to make progress toward European Union membership, but EU-sponsored normalization talks have sputtered in recent months.