Armed police could be seen escorting the detainees in Belgrade
The speaker of the Kosovan parliament has called on Serbia to free 10 suspected former Kosovo Liberation Army fighters it accuses of war crimes.
Police in the south Serbian region of Presevo seized them on Friday on suspicion of abductions, murders and rapes during the conflict in 1999.
They are said to include Kosovans visiting relatives in Presevo, which has a big ethnic Albanian population.
Serbia continues to regard Kosovo as part of its own territory.
Jakup Krasniqi, speaker of a parliament not recognised by Belgrade, said in a statement that the arrests were "intended to make Albanians and Serbs enemies and provoke Kosovo".
"We call upon the authorities of Belgrade to be responsible at these important historic moments the region and our two countries are going through," he said.
"In this regard we expect the release of the arrested citizens."
'Months of preparation'
The Serbian war crimes prosecutor's office said the suspects were part of a group which had sought to get rid of Serbs and other non-Albanians from Gnjilane (Gjilan in Albanian), 47km (30 miles) south-east of the Kosovan capital, Pristina.
"From June 1999 until October 1999, they were involved in at least 51 murders and 159 abductions in the town," said spokesman Bruno Vekaric.
The arrests were made in raids on 17 homes in Presevo after months of preparation because of the "extremely high risk as almost all the suspects were armed", the office added.
Nine suspects were transferred to custody in Belgrade while one remained under investigation in southern Serbia.
Ethnic Albanian militants in Presevo waged an insurgency against Belgrade in 2001 which was ended with the help of Nato and EU diplomacy.
Speaking on Saturday, Interior Minister Ivica Dacic said he accepted the arrests risked provoking a reaction "from those who were affected by the operation and who participated in war crimes against Serbs", Serbian TV reports.
But he stressed that the interior ministry had in the past arrested "a number of Serbs who held very important posts in the police because of crimes against Albanians", and appealed to ethnic Albanians in Presevo to co-operate with the police.