Indonesia,South Korea and Australia skipped the launch of a China-backed Asian infrastructure bank on Friday as the US said it had concerns about the new rival to Western-dominated multilateral lenders.

China’s proposed $50 billion Asian Infrastructure Investment Bank is seen as a challenge to the World Bank and Asian Development Bank, both multilateral lenders that count Washington and its allies as their biggest financial backers.

China, which is keen to extend its influence in the region, has limited voting power over these existing banks despite being the world’s second-largest economy.