Though officials in Kosovo blamed Serbians for a flare up of border violence, the Serbian president said diplomacy was the best way to resolve any conflict. NATO's Kosovo Force said border positions in northern Kosovo were attacked by unknown assailants. Both sides were urged to exercise restraint after Kosovo sent a police unit to the northern border to enforce a trade embargo on Serbia. NATO forces were deployed to the region to quell the violence. Kosovar Prime Minister Hashim Thaci blamed Serbia for the skirmish though Serbian President Boris Tadic was quoted by Russia's state-run news agency RIA Novosti as saying his country "will not go to war" over border violence. The news agency adds that unknown gunmen had fired on helicopters carrying Croatian peacekeepers though no injuries were reported. KFOR officials in a statement praised the people of Kosovo "because they haven't been led into violence or aggression." One border crossing is closed because parts of the infrastructure there are heavily damages. "Small private cars may cross the boundary on their own risk," the NATO force said in a statement. "However they will be checked by KFOR and searched for weapons and other prohibited goods."