Strasbourg - The Council of Europe yesterday condemned acts of vengeance against Serbs in Kosovo. Lord Russell-Johnston, president of the council's parliamentary assembly, said Kosovo Albanians should realise that ethnic violence was a boomerang, and always finished by striking those who initiated it. A report published earlier yesterday by the UN refugee agency (UNHCR) and the Organisation for Security and Co-operation in Europe (OSCE) said Serbs and Roma in Kosovo were victims of violence.