Until last month, the local UN-run police force was comprised of both Serb and ethnic Albanian officers.
Kosovo, where 90 per cent of the two million residents are ethnic Albanian, declared independence from Serbia last month.
Serbia, which considers Kosovo the historic cradle of its nation, denounced the declaration as invalid under international law.
"The Serb police officers are answering to the local Serb authorities and work under the command" of the UN police in Kosovo, the Belgrade document said.
Hajredin Kuqi, Kosovo's deputy prime minister, rejected the proposal saying it was "reminiscent of the old way of thinking".
Vojislav Kostunica, Serbia's prime minister and other Serbian officials, marked the anniversary of the Nato bombings by attending a service at St Marko's church in Belgrade, commemorating Serbs who died in the air raids.
Kostunica said that the ultimate aim of the bombing had been a Nato takeover of Kosovo.
"Now it is more than clear that the merciless destruction of Serbia in the Nato bombing had only one goal, and that is to turn Kosovo into the first Nato state in the world," he said.
In the Kosovo capital Pristina, Fatmir Sejdiu, the country's president, thanked the alliance for the campaign that "stopped the aggression of Serbia's military and paramilitaries against the people of Kosovo.
"We express our deepest gratitude and thanks to the US, EU ... for helping Kosovo when our people were threatened by extinction".
An estimated 1,200 to 2,500 people were killed in the bombing campaign which came after the collapse of talks aimed at ending the conflict between forces loyal to Slobodan Milosevic, Yugoslavia's president, and separatist ethnic Albanian guerillas.
Meanwhile, in Moscow, Vladimir Putin, Russia's president, ordered the government to send humanitarian aid to Serb-populated areas of Kosovo.
Russia backs Serbia's opposition to Kosovo independence, but Putin said that the gesture should not bear political overtones.
"If humanitarian aid is needed, let's do it, but without political colouring," he said.