LONDON, Nov 19 - The dollar extended gains above 109 yen on Wednesday, rising one percent on the day as traders grew increasingly wary Japanese authorities were acting to curb yen strength. London traders said they suspected Japanese authorities were selling yen for dollars after the dollar fell to three-year lows near 107.50 yen in European trade, although there was no official confirmation immediately available from Tokyo. The dollar has been under pressure across the board on concerns about U.S. trade measures against China and the gaping U.S. current account deficit. "I think this is the second bout of intervention coming from Tokyo," said a London-based dealer. "It looks like the dollar could head to 109.70 yen and this intervention might trigger a general dollar correction." The dollar was trading at the day's highs of 109.11 yen at 1008 GMT. The euro also rose by half a percent against the yen to six-week highs above 130.||www..com