Iran has been approved as a founding member of the Beijing-backed Asian Infrastructure Bank (AIIB), China’s finance ministry said Tuesday, just days after Tehran sealed a historic framework agreement on its nuclear program.

Iran has been approved as a founding member of the Beijing-backed Asian Infrastructure Bank (AIIB), China's finance ministry said Tuesday, just days after Tehran sealed a historic framework agreement on its nuclear program.

Tehran's application was backed by other founding members on Friday, China's Ministry of Finance said in a statement on its website. The United Arab Emirates' bid was also approved.

More than 50 countries, plus Taiwan, have now applied to join the bank in a diplomatic coup for Beijing after Washington initially opposed its allies becoming members.

The United States and its Asian ally Japan have not sought to join.

But US Treasury Secretary Jacob Lew said last week that Washington was "ready to welcome" the bank, though he added it should complement existing multilateral institutions such as the World Bank and International Monetary Fund.

Iran's approval -- its application had not been previously announced -- comes immediately after the nuclear deal that China helped to broker.