The United Nations hopes to open "final status" talks on Kosovo in September, provided the province in southern Serbia proves its democratic credentials.

But a pattern of almost daily acts of violence this month - some aimed at international officials - is worrying Kosovo's UN overseers and the 18,500-strong NATO-led peace force.

With no guarantee that Kosovo will become independent of Serbia, some UN officials say Albanian "extremists" want to escalate tensions in the hope that they can stampede the UN into giving them what they want and getting out. 

"This is a warning and an expression of fear," a senior UN official said on condition of anonymity. "Under the surface it's boiling, and it could really escalate."

On 8 March, Kosovo prime minister and former rebel leader Ramush Haradinaj resigned after he was charged with war crimes during the 1998-99 guerrilla war against Serb forces.

Riots

He left for the UN tribunal the next day and Kosovo held its breath. NATO deployed an extra 1000 troops but an anticipated backlash from his supporters never happened.

The West praised Kosovo's democratic maturity, relieved to see no repeat of riots in March last year in which 19 people died and hundreds of Serb homes were torched.

"This [violence] is a warning and an expression of fear. Under the surface it's boiling, and it could really escalate"

Senior UN official

But the absence of marauding mobs masks a steady rise in incidents that fail to make the news - a hand grenade lobbed at a UN vehicle, an anti-tank mine found under another, a blast outside the main UN compound, shots at its satellite dish.

"There's been an increase to almost one per day," Kai Vittrup, the Danish head of the 3000-strong UN police force, said. He also described them as a "warning" by groups uninterested in democratic methods.

The more serious attacks included a bomb blast targeting President Ibrahim Rugova's convoy on 15 March, which he escaped from unhurt, and a vicious attack on two elderly Serbs on Monday, for which there have as yet been no arrests.

The latter coincided with a two-day trip by Kosovo's UN governor to Belgrade where he met Serb leaders, an unpopular move among Kosovo Albanians who fear a return to Serb rule.

Serb demands

Serbia says independence for the land it considers sacred is impossible. It lost control over Kosovo in 1999 after a NATO bombing campaign to expel Serb forces accused of atrocities against civilians as they fought separatist guerrillas.

Ethnic Albanians want nothing
less than Kosovan independence

After six years of UN-imposed limbo, the 90% Albanian majority will accept nothing less than independence, but Western powers remain publicly non-committal, fuelling uncertainty among Kosovo's two million people.

An influential Brussels think-tank warned in January of new conflict if there is no move to independence this year.

It said mass unemployment was a breeding ground for unrest and only an end to uncertainty could rescue the economy.

Analysts say some ethnic Albanian groups want the UN to be aware of what could happen, should independence be denied or even delayed.

"Independence is unclear, people don't see a light at the end of the tunnel," the UN source said. "These young men don't have anything to lose. All they've seen is that crime pays."