Calls for a military intervention in Syria are an \"undisguised challenge\" to the United Nation charter, the Russian foreign ministry said Thursday. \"Declared plans by some states to inflict a military strike on Syria are an undisguised challenge to the key provisions of the UN charter and other norms of international law,\" the statement quoted deputy foreign minister Gennady Gatilov as telling UN Secretary General Ban Ki-moon at a meeting at The Hague on Wednesday.