Former Prime Minister of Kosovo Ramush Haradinaj has surrendered to The Hague war crimes tribunal after arriving in the Netherlands from Pristina.
Ramush Haradinaj has urged calm in the province
Mr Haradinaj resigned as head of his government on Tuesday after he was indicted on war crimes charges.
His indictment refers to his role in the 1998-99 Kosovo conflict, although the charges have not been made public.
Mr Haradinaj, a former commander of the Kosovo Liberation Army (KLA), says he is innocent.
He was taken to the UN detention unit under police escort after arriving on a special flight from the Kosovo capital.
He is due to appear in court in the next few days where he will be asked to plead to the charges in his indictment, which is expected to be released shortly.
He urged calm in the UN-administered Serbian province, which is dominated by ethnic Albanians, when he announced his resignation.
"I have been called upon to make a sacrifice, something I never believed would happen," he said.
"This means also co-operation with international justice, however unjust it is."
Nato has deployed additional 1,000 troops in the province to bolster the Nato-led Kosovo Protection Force (K-For) mission, amid reports that ethnic Albanians would hold protests.
Serbia and the European Union have also appealed for calm.
In a statement, EU foreign policy chief Javier Solana said: "I welcome the decision of Ramush Haradinaj to co-operate with the ICTY [International Criminal Tribunal for former Yugoslavia]."
US state department spokesman Richard Boucher said Mr Haradinaj's actions "demonstrate his deep concern for the future of Kosovo and its people".
The head of the UN mission in Kosovo, Soren Jessen-Petersen, also praised Mr Haradinaj's decision.
Mr Haradinaj, 36, is also wanted by Belgrade for alleged war crimes committed against Serb civilians during the war.
During the conflict, Mr Haradinaj led ethnic Albanian guerrillas in Kosovo's western region.
Supporters of the former prime minister gathered at Pristina airport
Soldiers under his command were accused of killing Serbs and other non-Albanian civilians.
Kosovo has been administered by the UN since the Nato bombing campaign drove out Serb forces in 1999.
In December, Mr Haradinaj was overwhelmingly endorsed by Kosovo's parliament.