Unexploded cluster bombs threaten thousands of Serbian civilians almost 10 years after they were dropped during Nato's 1999 air war over Kosovo.

Nobel Peace Prize laureate Martti Ahtisaari said on Friday that Serbia would have no option but to accept the new Balkan state.

Carla del Ponte, the former chief prosecutor for war crimes in former Yugoslavia, has unleashed a storm of recrimination with allegations of a trade in human body parts in Kosovo and Albania after Nato bombed Serbia in 1999. Del Ponte's claims are based on what she describes as credible reports and witnesses.

The worst ethnic violence in Kosovo since the end of the 1999 conflict erupted in the partitioned town of Kosovska Mitrovica on Wednesday, leaving hundreds wounded and at least 14 people dead. United Nations peacekeepers and Nato troops scrambled to contain a raging gun battle between Serbs and ethnic Albanians.