The China-backed Asian Infrastructure Investment Bank (AIIB) is expected to hold its opening ceremony in mid-January, Chinese state media quoted the bank's deputy head as saying. China News Agency also quoted Chen Hun as telling a conference at least 50 percent of members will have ratified the AIIB's constitution after India and Russia sign this month, allowing the bank to begin operations. Chen also was quoted saying the bank, while waiting for a credit rating, will probably begin issuing unrated bonds that will be "supported" by South Korea. He said he expects South Korea to play an active role in AIIB. The bank's president-elect Jin Liqun was recently in Seoul, during which he urged Korean institutional investors to support AIIB. An official of South Korea's finance ministry, told about Chen's Thursday comments, noted the Seoul government "has said it would provide support as needed in the form of encouragement or provision of information. But in any case, the support won't be any formal one." The AIIB, seen as a rival to the World Bank, is expected to lend $10 billion -$15 billion a year in its initial years, Jin Liqun said. According to the AIIB's draft business plan and budget, it plans to issue between $100 million to $500 million of bonds in its first year, though the final amount still requires approval, he added. First proposed by President Xi Jinping less than two years ago, the bank has become one of China's biggest foreign policy successes. Despite the opposition of Washington, almost all major U.S. allies - Australia, Britain, German, Italy, the Philippines and South Korea - have joined.