The logo of Asian Infrastructure Investment Bank (AIIB) is seen at its headquarter building in Beijing January 17, 2016. REUTERS/Kim Kyung-Hoon

BEIJING (Reuters) - The board of the Asian Infrastructure Investment Bank (AIIB) has approved the applications of Argentina, Madagascar and Tonga to be members, the China-backed multilateral development bank said.

The three prospective members will officially join once they complete the required domestic processes and deposit the first installment of capital with the bank, AIIB said in an emailed statement on Friday.