Pristina  - A top Kosovo Albanian politician Friday accused Belgrade of dangerously raising tensions by sending police to illegally control the northern, Serb-dominated section of Kosovo.

Belgrade and Kosovo Serbs rejected the declaration of independence by Kosovo in February, as well as the new country's constitution, which went into effect on Sunday.

"Kosovo's northern part is controlled and patrolled by Serbia's ministry of interior," the mayor of Kosovska Mitrovica, Bajram Rexhepi, told reporters.

He said he has asked the NATO-led peacekeeping mission (KFOR) and United Nations police to assert control over the northern one-quarter of Kosovo bordering Serbia-proper, where Serbs are a total majority.

Kosovo was recognized by leading Western powers, but Russia has blocked its promotion in the UN. Moscow supports Belgrade's proprietorial claims with regard to Kosovo.

Northern Kosovo is currently quiet, said Rexhepi, a former Kosovo premier, but warned that the situation may deteriorate owing to the "increased activity of Serbia's parallel structures."

Serbia encourages Serbs in Kosovo north of Mitrovica to boycott central authorities in Pristina and to keep cooperation with the outgoing UN administration at a minimum.

When Kosovo declared independence in February, Serbia backed rioting by Serbs in the north, in which one Ukrainian policeman and one protester were killed.

Wary of an explosion of violence, neither international missions, nor central Pristina authorities moved to stomp out the riots and Serbia's influence in the north.

Serbia lost control over Kosovo, which it still considers its province, when NATO ousted its army and police from there in 1999 to end repression of the 2.1 million Albanians, a 90-per-cent majority.

The UN mission which governed Kosovo since then is due to be replaced by a lighter, law-enforcing presence sent by the European Union, but its departure is being blocked by Serbia's ally Russia.

The Serbs are a majority along the border with Serbia proper, in the northern one-quarter of Kosovo's territory. Belgrade now pushes to assert more influence there and so deepen the factual partition of Kosovo along ethnic lines. (dpa)