MOSCOW (AFP) - President Dmitry Medvedev on Monday slammed Prime Minister Vladimir Putin's comments on military action against Libya as "unacceptable", in the most public clash yet between Russia's ruling tandem. Putin earlier Monday had slammed the UN resolution allowing military action on Libya as resembling a "medieval call to crusade", in one of his most virulent diatribes against the West in years. "Under no circumstances is it acceptable to use expressions which essentially lead to a clash of civilizations. Such as 'crusade' and so on," Russian news agencies quoted Medvedev as saying.