The UN administration ordered "stringent measures" for security Sunday in Serbia's province of Kosovo hours after a grenade attack on a bus which caused no injuries.

Soren Jessen-Petersen, Kosovo's top UN official, ordered police to step up patrolling and erect checkpoints throughout the province following the overnight assault.

Declaring the "stringent measures to enhance security," Jessen-Petersen blasted "isolated individuals or groups" for trying to derail the on-going status talks.

"Incidents such as the one last night demonstrate that, during the status process which has just begun, isolated individuals or groups who do not have Kosovo's best interests in mind may attempt to disrupt Kosovo's way forward for their own ulterior motives," he said in a statement.

The bus carrying ethnic Albanians and people belonging to several ethnic minorities, including one Serb, was hit late Saturday near the southern town of Prizren. The rocket-propelled grenade pierced the passenger compartment, but failed to explode. NATO peacekeepers later defused the projectile.

The attack, the latest in a series of shootings and small bomb blasts in the last six months, was linked to the recent launch of talks on the future status of the province, where ethnic Albanians make up 90 percent of the 2 million population.

UN envoy Martti Ahtisaari is on a shuttle mission to prepare direct talks in early 2006 on the future status of Kosovo.

Just before kicking off a tour to the troubled province last month, Ahtisaari came under threat by a self-styled Kosovo Independence Army (KIA) to attack the provincial capital of Pristina.

"It is very likely that the city of Pristina, whose institutions are under the control of the modern occupier, will be the target of our independence forces starting on Nov. 23," said a KIA statement.

"We believe that the UNMIK (the United Nations Mission in Kosovo) forces will not only be unable to stop our operations, but will be asking for a corridor to be made by our troops in order for them to flee in shame," the statement said.

Kosovo has been under UN control since a NATO-led bombing campaign in 1999 forced the withdrawal of Serbian troops from the province.

But tensions remain high, with the local ethnic Albanians demanding independence, a move rejected by Belgrade.

Source: Xinhua