American competitiveness is at stake as Congress considers whether to support a global tax accord that imposes minimum levies and stricter regulations on corporations, according to a top U.S. Treasury official.

The accord, backed by 137 countries, would remake an international tax system that's for years seen countries undercut each other's corporate tax rates. The average rate in major economies has tumbled to 23 percent, from 40 percent four decades ago.

"This race to the bottom means that not only are corporate tax rates driven down, but so are government resources, which could be used to build infrastructure, educate and train our citizens, incentivize R&D, and combat climate change," Lily Batchelder, the assistant Treasury secretary for tax policy, said in prepared remarks to a New York State Bar Association event that were obtained by Bloomberg.