Nato has said it will still be on hand to react if necessary
Nato forces in Kosovo have handed over the task of guarding the Gazimestan monument, a site of great historical significance to Serbs, to local police.
The move is seen as an important step in the transfer of powers to local authorities. It has angered Serbia.
Gazimestan marks the site of the 1389 Battle of Kosovo against the Ottomans.
It is where Slobodan Milosevic rallied Serb activists 600 years later, with a nationalist speech that propelled him to power.
The Kosovo police force is dominated by ethnic Albanians.
Although some Serbs have joined, it is under the control of the Kosovan government, which Serbia refuses to recognise.
Belgrade considers Kosovo as a southern province and rejects the declaration of independence by the Albanian majority two years ago.
Nato's choice of Gazimestan as the first monument to be protected by the Kosovan police service is highly significant, the BBC's Mark Lowen reports from Belgrade.
The Serbian government has criticised the transfer of powers.
It claims that Serbian monuments have been subject to past attacks by "Albanian extremists", who - it has said - aim to destroy all traces of the Serb presence in Kosovo.
Nato has told the BBC it will remain available to react if necessary, our correspondent adds.