tallinn/vilnius plan radars ship baltics nato officials say watch russia big war game since 2013 calm confidence many unnerve see moscow test ability wage war west nato believe exercise officially start thursday belarus baltic sea western russia russian exclave kaliningrad already underway say large moscow publicize number 100,000 troop involve fire nuclear-capable ballistic missiles codenamed zapad west nato officials say drill simulate conflict u.s.-led alliance intend show russia ability mass large number troop short notice event conflict nato remain calm vigilant nato secretary-general jens stoltenberg say last week visit estonian army base british troop station since march lithuania defense minister raimundas karoblis less sanguine voice widely-felt fear drill risk trigger accidental conflict could allow moscow leave troop neighbor belarus totally calm large foreign army mass next lithuanian territory tell reuters western officials include head u.s. army europe gen. ben hodges raise concern russia might use drill trojan horse make incursions poland russian-speaking regions baltics kremlin firmly reject plan russia say 13,000 troop russia belarus involve sept. 14-20 drill international threshold require large number outside observers nato send three experts so-called visitor days exercise nato official say substitute meet internationally-agreed norms exercise include talk soldier brief moscow say west threaten stability eastern europe u.s.-led nato alliance put 4,000-strong multinational force baltics poland wrong-footed moscow recent past russia seizure crimea 2014 intervention syria war 2015 nato distrustful kremlin public message crimea moscow prove master hybrid warfare mix cyber attack disinformation campaign use russian local force without insignia one senior european security official say zapad would merge manoeuvre across russia four western military district complex multi-dimensional aggressive anti-nato exercise smoke mirror official say add soviet-era zapad exercise revive 1999 include simulate nuclear strike europe nato officials say watch russia preparations months include use hundreds rail cars carry tank heavy equipment belarus precaution u.s. army move 600 paratroopers baltics zapad take guardianship airspace lithuania latvia estonia lack capable air force air defense systems russia military show force raise uncomfortable question alliance nato yet mass large number troop quickly despite unite state military might nato officials diplomats say nato 29-nation defense pact create 1949 deter soviet threat already begin big modernization since cold war send four battalions baltics poland set agile high-readiness spearhead force develop cyberspace defenses nato deliberately take slowly-slowly approach military build-up avoid suck new arm race even russia station anti-aircraft anti-ship missiles kaliningrad black sea syria last thing want military escalation russia say one senior nato official involve military plan refer zapad event potential russian incursion baltics poland nato new multinational force would quickly need large reinforcements 40,000-strong force agree 2015 still develop officials say lithuania karoblis say hop see progress next summit nato leaders july 2018. baltic politicians want discretion give nato fight aggressor event attack without wait go-ahead ally governments zapad nato take low-key approach run exercise include annual sniper exercise lithuania non-nato member sweden hold large-scale drill nato deputy supreme ally commander europe jam everard tell reuters need mirror zapad competition say visit nato force latvia russia 's zapad war game unnerve west