The idea of a technical default -- essentially delaying interest payments for a few days -- has gained backing from a growing number of mainstream Republicans who see it as a price worth paying if it forces the White House to slash spending, Reuters reported on Tuesday.
But any form of default could destabilize the global economy and sour already tense relations with big U.S. creditors such as China, government officials and investors warn.
Li Daokui, an adviser to the People's Bank of China, said a default could undermine the U.S. dollar, and Beijing needed to dissuade Washington from pursuing this course of action.
"I think there is a risk that the U.S. debt default may happen," Li told reporters on the sidelines of a forum in Beijing. "The result will be very serious and I really hope that they would stop playing with fire."
China is the largest foreign creditor to the United States, holding more than $1 trillion in Treasury debt as of March, U.S. data shows, so its concerns carry considerable weight in Washington.
"I really worry about the risks of a U.S. debt default, which I think may lead to a decline in the dollar's value," Li said.
Congress has balked at increasing a statutory limit on government spending as lawmakers argue over how to curb a deficit which is projected to reach $1.4 trillion this fiscal year. The U.S. Treasury Department has said it will run out of borrowing room by August 2. (read more)