BELGRADE, Serbia (AP) -- Tensions between Serbia and Kosovo flared anew this week after Kosovo's police raided Serb-dominated areas in the region's north and seized local municipality buildings.
There have been violent clashes between Kosovo's police and NATO-led peacekeepers on one side and local Serbs on the other, leaving dozens of people injured on both sides.
Serbia raised the combat readiness of its troops stationed near the border and warned it wouldn't stand by if Serbs in Kosovo were attacked again. The situation has again fueled fears of a renewal of the 1998-99 conflict in Kosovo that claimed more than 10,000 lives and left more than 1 million homeless.
WHY ARE SERBIA AND KOSOVO AT ODDS?
Kosovo is a mainly ethnic Albanian populated territory that was formerly a province of Serbia. It declared independence in 2008.
Serbia has refused to recognize Kosovo's statehood and still considers it part of Serbia, even though it has no formal control there.
Kosovo's independence has been recognized by about 100 countries, including the United States. Russia, China and five EU countries, most of them with separatist regions of their own, have sided with Serbia. The deadlock has kept tensions simmering and prevented full stabilization of the Balkan region after the bloody wars in the 1990s.
HOW DID SERBIA'S ALLIES REACT?
Russian Foreign Minister Sergei Lavrov said the situation in Kosovo was alarming and that it could provoke another conflict in the heart of Europe.
"A huge explosion is being prepared in the center of Europe, in the place where, in 1999, NATO attacked Yugoslavia, violating every imaginable (international) principle," he said, according to Russian state news agency RIA Novosti.
China said that it was closely following the developments.
Chinese Foreign Ministry spokesperson Mao Nin urged NATO to respect the sovereignty and territorial integrity "of the relevant countries and truly do what is conducive to regional peace."
WHAT'S THE LATEST FLARE-UP ABOUT?
Serbs boycotted last month's local elections held in northern Kosovo, where they represent a majority. Last Friday, newly elected ethnic Albanian mayors moved into their offices with the help of Kosovo's riot police.
Serbs tried to prevent them from taking over the premises, but the police fired tear gas to disperse them.
On Monday, Serbs engaged in fierce clashes with NATO peacekeepers, leaving more than 50 rioters and 30 international troops injured.
The election boycott followed a collective resignation by Serb officials from the area, including administrative staff, judges, and police officers, in November 2022.
WHAT IS NATO DOING IN KOSOVO?
Till now, there have been some 3,800 NATO troops stationed in Kosovo, primarily on peacekeeping duties, but also to watch over the borders, especially the one with Serbia where Belgrade has currently been beefing up its troop presence.
NATO Secretary-General Jens Stoltenberg said Tuesday the alliance had sent 700 more troops to Kosovo to help quell violent protests and had put another battalion on standby in case the riots spread.
HOW DEEP IS THE ETHNIC CONFLICT IN KOSOVO?
The dispute over Kosovo is centuries-old. Serbia cherishes the region as the heart of its statehood and religion.
Numerous medieval Serb Orthodox Christian monasteries are in Kosovo. Serb nationalists view a 1389 battle against Ottoman Turks there as a symbol of its national struggle.
Kosovo's majority ethnic Albanians view Kosovo as their country and accuse Serbia of occupation and repression. Ethnic Albanian rebels launched a rebellion in 1998 to rid the country of Serbian rule.
Belgrade's brutal response prompted a NATO intervention in 1999, which forced Serbia to pull out and cede control to international peacekeepers.
HAVE THERE BEEN ATTEMPTS TO RESOLVE THE DISPUTE?
There have been constant international efforts to find common ground between the two former wartime foes, but there has been no final comprehensive agreement so far.
EU officials have mediated negotiations designed to normalize relations between Serbia and Kosovo. Numerous agreements have been reached, but were rarely implemented on the ground. Some areas have seen results, like introducing freedom of movement within the country.
WHO ARE THE MAIN PLAYERS?
Both Kosovo and Serbia are led by nationalist leaders who have shown no readiness to compromise.
In Kosovo, Albin Kurti, a former student protest leader and political prisoner in Serbia, leads the government and is the main negotiator in EU-mediated talks. He was also known as a fierce supporter of Kosovo's unification with Albania and is against any compromise with Serbia.
Serbia is led by populist President Aleksandar Vucic, who was information minister during the war in Kosovo. The former ultranationalist insists that any solution must be a compromise in order to last and says the country won't settle unless it gains something.
WHAT HAPPENS NEXT?
International officials are hoping to speed up negotiations and reach a solution in the coming months.
Both nations must normalize ties if they want to advance toward EU membership. No major breakthrough would mean prolonged instability, economic decline and constant potential for clashes.
Any Serbian military intervention in Kosovo would mean a clash with NATO peacekeepers stationed there.