Following the Republic of Kosovo's formation of the Kosovo Security Forces in January 2009, he sent protest letters both to the and NATO Secretaries-General. The letter states that Serbia views those forces as an illegal paramilitary organisation that constitutes a threat to the country's security and a danger to peace and stability in the Western Balkans. Tadić drew attention to the fact that the KSF were formed on the basis of the Ahtisaari Plan that was never adopted by the Security Council and added that the creation of these forces constitutes a breach of the Serbian Constitution and international law, which is why they should be disbanded. He called for the demilitarisation of Kosovo.