Washington has questioned whether the new bank, the Asian Infrastructure Investment Bank (AIIB), will have high standards of governance and environmental and social safeguards.
"I hope before the final commitments are made anyone who lends their name to this organization will make sure that the governance is appropriate," U.S. Treasury Secretary Jack Lew told U.S. lawmakers.
Lew warned the Republican-dominated Congress that China and other rising powers were challenging American leadership in global financial institutions, and he urged lawmakers to swiftly ratify stalled reform of the IMF.
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German Finance Minister Wolfgang Schaeuble announced at a joint news conference with visiting Chinese Vice Premier Ma Kai that Germany, Europe's biggest economy and a major trade partner of Beijing, would be a founding member of the AIIB.
In a joint statement, the foreign and finance ministers of Germany, France and Italy said they would work to ensure the new institution "follows the best standards and practices in terms of governance, safeguards, debt and procurement policies."
Luxembourg's Finance Ministry confirmed the country, a big financial center, has also applied to be a founding member of the $50 billion AIIB.
The AIIB was launched in Beijing last year to spur investment in Asia in transportation, energy, telecommunications and other infrastructure. It was seen as a rival to the Western-dominated World Bank and the Asian Development Bank. China has said it will use the best practices of those institutions.
A spokeswoman for the European Commission, the EU's executive arm, endorsed member states' participation in the AIIB as a way of tackling global investment needs and as an opportunity for EU companies.
The bank is seen as a means to spread Chinese "soft power" in the region, possibly at the expense of the United States, which is pursuing its own Asian strategy to strengthen its military and economic presence there.
The World Bank is traditionally run by a U.S. nominee and Washington also has the most influence at the IMF.
The adjustment of shares and voting rights in the IMF was brokered by Britain at a Group of 20 summit in 2010, and European countries ratified it long ago.
Lew told lawmakers that the U.S. delay was undermining its credibility and influence as countries question the United States' commitment to international institutions.
"It's not an accident that emerging economies are looking at other places because they are frustrated that, frankly, the United States has stalled a very mild and reasonable set of reforms in the IMF," Lew said.
China said earlier this year a total of 26 countries had been included as AIIB founder members, mostly from Asia and the Middle East. It plans to finalize the articles of agreement by the end of the year.