theoceans, including undertheArcticice-cap, everyendeavour ismadebySSBNsto remainentirely undetected atalltimes,despite theconsiderable efforts thatare madetolocate andtrailthemfromthemomenttheyleaveharbour totheirreturnat theendoftheirpatrols. Theseactivities, whichuptonowhavetakenplace continuously intheworld's northern oceans andseas,arouse concerns onthepart ofStates whichdonotparticipate inthem. 259.Inthatworldsecurity isheldhostage tothestrategic nuclear policies of thenuclear-weapon States, inparticular thoseoftheSoviet UnionandtheUnited States, theunceasing deployment ofsuchstrategic nuclear forcesatsea constitutes themostpotentnavalcapability endangering international peaceand security. Thearguments onthepartofsomethatsuchdeployments represent successful mutualdeterrence aretoothersinsubstantial andinadequate protection against theprospect ofmisunderstanding, technical faultorhumanerrorunleashing anuclear exchange whichwouldaffectthewholeworld. Inbrief,intheviewof theoverwhelming majority ofStates, thepossible consequences aretoodisastrous towarrant thesmallest riskandtherefore measures ofnuclear disarmament are urgently needed. 260.Atadifferent level,thenumbers andextentofthedeployment oftactical nuclear weapons alsogiverisetoverygreatconcern. Asindicated inchapterIll, manyofthewarships, submarines andaircraft ofthenuclear-weapon States canbe considered nuclear-capable and,asfarascanbeascertained, therewouldappearto beawideavailability inservice oftactical nuclear weapons, inclUding short-range missiles. Inthewide-open spacesoftheoceanitispossible touse tactical nuclear weapons inamilitary encounter without direct damagetocivilian lifeorproperty. Notwithstanding theexistence ofrigorous control procedures, it ispossible toenvisage circumstances inwhichsuchusemightbeinitiated. Such I ...A/40/535 English Page72 possibilities mighteasilyleadtoahighlydangerous reaction orresponse which couldhavegraveimplications forinternational security asawhole. Inaddition, thereareimportant questions concerning custody onboard,safety incasesof collision andtheabsolute reliability ofcontrol systems inpeacetime, eventhough thenuclear-weapon Statesmaintain thatinfacttheirsafetyrecordtodatehas beensound. Overall, veryserious doubts remain onthepartofnon-nuclear-weapon States concerning theassurances given bythepresent fivenuclear-weapon States on theseissues. 261.Thereisalsotheveryrealdifficulty ofexternally identifying whichships, submarines oraircraft areactually carrying tactical nuclear warheads. In addition, withsubmerged submarines thereisthefurther difficuYEy ofidentifying eventheirnationality andofestablishing communications withthem.Inthis regardthedevelopment Ofsea-launched cruisemissiles, ortorpedoes, capable of carrying either anuclear oraconventional warhead creates extremely complex verification problems. Whileaccepting thatbecause ashipis nucleac-weapon-capable itdoesnotnecessarily meanthatsuchweapons areonboard, thewideavailability oftactical nuclear weapons thatnowappears toeXist, and thecustom ofcertain nuclear-weapon Statesneither toconfirm nortodenythe presence onboardofnuclear weapons, willraiseverydeepmisgivings onthepart ofnon-nuclear-weapon States whenrequested toallowsuchvessels topayport visits orentertheirterritorial waters. Therefore, torseveral reasons, early consideration should begiven bythenuclear-weapon Statestoagreeoneffective measures ofcurtailing thenumbers anddeployment oftactical nuclear weapons. 262.Theworld-wide capabilities ofthegeneral-purpose navalforcesoftheUnited States andtheSoviet Unionalsohavesignificant international security implications. Toalesserextent, therecanbesimilar effects fromtheactivities ofsomeoftheblue-water navies. 263.Inthefirstinstance, aspartoftheirrespective alliance arrangements the naviesofthememberStatesofNATOandWTOregularly conduct exercises, including amphibious exercises, andtakepartintraining. Whilesuchactivities are considered bytheirrespective participants aspartoftheircollective defence arrangements, Statesoutside thosealliances oftenconsider themtobe
**Analysis**
The text appears to be discussing the deployment and implications of nuclear weapons by various countries, particularly the United States and the Soviet Union. It highlights concerns about the potential risks and consequences of such deployments, including the possibility of misunderstandings, technical faults, or human errors leading to a nuclear exchange. The text also touches on the issue of verifying the presence of nuclear weapons on ships, submarines, and aircraft.

**Category**
International security, Science and technology