moscow russian foreign minister sergei lavrov say friday risk military conflict north korea nuclear program high moscow deeply worry mutual threats trade washington pyongyang unfortunately rhetoric washington pyongyang start go top lavrov say still hope believe common sense prevail ask forum russian students risk stand-off escalate arm conflict say risk high especially take account rhetoric direct threats use force hear ... talk washington must preventive strike make north korea pyongyang threaten carry missile strike u.s. base guam threats continue non-stop worry us lot get guess happen whatever prevent personal opinion get close point fight break side strong clever take first step away threshold danger say lavrov remark broadcast state television encourage pyongyang washington sign joint russian-chinese plan north korea would freeze missile test unite state south korea would impose moratorium large-scale military exercise double freeze finally take place sit start begin sign paper stress respect sovereignty party involve include north korea lavrov say russia say bellicose rhetoric north korea 'over top