TOKYO/SYDNEY, (Reuters) – Japan signaled cautious approval of the China-led Asian Infrastructure Investment Bank (AIIB) on Friday and said for the first time that, if conditions were met, it could join the institution that the United States has warned against. Australian Treasurer Joe Hockey said there was “a lot of merit” in the bank and the Sydney Morning Herald newspaper reported that Canberra could formally decide to sign up when the full cabinet meets on Monday. Japan, Australia and the South Korea, all major U.S. allies, are the notable regional absentees from the AIIB.