Russia, Australia, Denmark and the Netherlands have now become the latest countries to join the China-led Asian Infrastructure Investment Bank despite misgivings in Washington. China has set a March 31 deadline to become a founding member of the bank, which is seen as a significant setback to U.S. efforts to extend its influence in the region and balance China's growing financial clout and assertiveness. At least 35 countries will join the AIIB by the deadline, the bank's interim chief, Jin Liqun, said last Sunday.