▁Japan ▁to ▁admin ister ▁the ▁islands ▁as ▁part ▁of ▁the ▁South ▁Se as ▁Mand ate . ▁ ▁During ▁World ▁War ▁II , ▁a ▁significant ▁portion ▁of ▁the ▁Japanese ▁fleet ▁was ▁based ▁in ▁Tru k ▁L ago on . ▁In ▁February ▁ 1 9 4 4 , ▁Operation ▁H ail stone , ▁one ▁of ▁the ▁most ▁important ▁naval ▁batt les ▁of ▁the ▁war , ▁took ▁place ▁at ▁Tru k , ▁in ▁which ▁many ▁Japanese ▁support ▁vessels ▁and ▁aircraft ▁were ▁destroyed . ▁ ▁Following ▁World ▁War ▁II , ▁it ▁was ▁admin ister ed ▁by ▁the ▁United ▁States ▁under ▁United ▁Nations ▁aus p ices ▁in ▁ 1 9 4 7 ▁as ▁part ▁of ▁the ▁Trust ▁Territ ory ▁of ▁the ▁Pacific ▁Islands ▁purs u ant ▁to ▁Security ▁Council ▁Resol ution ▁ 2 1 . ▁ ▁On ▁May ▁ 1 0 , ▁ 1 9 7 9 , ▁four ▁of ▁the ▁Trust ▁Territ ory ▁districts ▁rat ified ▁a ▁new ▁constitution ▁to ▁become ▁the ▁Feder ated ▁States ▁of ▁Mic ron esia . ▁Pal au , ▁the ▁Marshall ▁Islands , ▁and ▁the ▁Northern ▁Mar iana ▁Islands ▁chose ▁not ▁to ▁particip ate . ▁The ▁F SM ▁signed ▁a ▁Comp act ▁of ▁Free ▁Association ▁with ▁the ▁United ▁States , ▁which ▁entered ▁into ▁force ▁on ▁November ▁ 3 , ▁ 1 9 8 6 , ▁mark ing ▁Mic ron esia ' s ▁emer gence ▁from ▁trust ees hip ▁to ▁independence . ▁Independ ence ▁was ▁formally ▁concluded ▁under ▁international ▁law ▁in ▁ 1 9 9 0 , ▁when ▁the ▁United ▁Nations ▁officially ▁ended ▁the