Some Albanians have been angered by the jailing of KLA members

The Indian officer, named as 43-year-old Satish Menon, died when his marked police car came under fire from a semi-automatic rifle from the side of the road near the town of Leposavic in the north of the province.

This is the first time a member of the international police force has been killed on duty in Kosovo since the UN took over responsibility for the province four years ago.

UN police are describing the attack as a well-planned ambush.

"It is clear that this was a sniper attack on an international police officer by cowards who intended to kill him," UN police chief Stefan Feller said in a statement.

Investigators say boulders had been placed in the road to make the car slow down and give the gunman time to shoot.

The driver of the officer's car was unscathed.

Members of the international police force travel in clearly marked red and white cars which distinguish them from members of the local police service.

The investigation is focusing on three ethnic Albanian villages close to the scene of the ambush.

Anti-UN sentiment

The area was the scene of another attack earlier this year.

Two members of a guerrilla group known as the Albanian National Army blew themselves up while attempting to mine a nearby bridge.

UN officials say it is too early to say what the precise motive for the attack was.

However the BBC's Nicholas Wood in the northern town of Mitrovica says there has been an increase in anti-UN sentiment in Kosovo over the last few weeks.