China will be the elephant in the room at this week’s summit of Group of Seven (G7) financial officials, who will aim to diversify supply chains away from the nation while simultaneously attempting to enlist Beijing’s assistance in resolving global debt concerns.

The contradictory ambitions add to the risks that the G7 affluent democracies confront as a result of their reliance on China, the world’s second-largest economy and the second-largest foreign holder of US debt.

The heightening risk of a U.S. debt default, which could jolt financial markets already jittery after recent bank failures, will overshadow the three-day meeting kicking off on Thursday in the Japanese city of Niigata.

While Treasury Secretary Janet Yellen will join the G7 finance leaders’ talks, U.S. President Joe Biden on Tuesday signalled the chance of cancelling his trip to Hiroshima for next week’s summit if the debt issue is not resolved.

“The dollar is regarded — and Treasury securities –as the bedrock safe asset in the entire global financial system,” Yellen said on Monday, in a warning of the damage a default could inflict on the U.S. economy and financial markets.

“It’s trusted, and it is the ultimate safe asset and a failure to raise the debt ceiling, impairing the U.S. credit rating, would put that at risk. So that is a real concern.”

The U.S. debt crisis is a headache for Japan, which is this year’s G7 chair and the world’s biggest holder of U.S. debt.

Other key themes to be discussed at this week’s G7 gathering include ways to strengthen the global financial system, steps to prevent Russia from circumventing sanctions over its invasion of Ukraine, and global economic risks such as stubbornly high inflation, Japanese officials say.

Japan hopes to issue a G7 joint statement after the meeting, they added.