U.S. Treasury Secretary Yellen warns that running out of cash on June 1 will trigger a "financial and economic collapse" if the debt ceiling is not raised

In an interview with ABC, she said:

Yellen said the U.S. was already using "extraordinary measures" to avoid a default, but this was not an approach the Treasury Department could use on a sustainable basis. There is no good way to avoid "economic disaster" other than congressional action to raise the debt ceiling..

Biden administration officials have considered whether they could invoke the 14th Amendment to the U.S. Constitution, an option the president had previously kept open amid stalled debt-ceiling talks. According to the amendment, Biden can continue to issue debt without raising the borrowing limit.

But Yellen warned that resorting to the 14th Amendment would trigger a constitutional crisis. She doesn't want to consider the emergency option yet, and using that provision would be "one of the bad options".
She said:

What I'm trying to say is that this is the job of Congress. If they fail to do this, we will face an economic and financial disaster - one of our own making, and nothing that President Biden and the US Treasury can do to prevent it.
In a letter to House Speaker McCarthy last Monday, Yellen said the debt ceiling could be breached as early as June 1. The date was earlier than Wall Street economists expected.
The U.S. Treasury Department has been using special accounting maneuvers to stave off a potential default on federal debt since January, when U.S. debt hit its current legal limit of $31.4 trillion. The White House and congressional Republicans are deadlocked over raising the $31.4 trillion debt ceiling.

Soon, interest will be the US government's largest expense.Each time the debt ceiling is raised, the crisis gets worse.We need a sustainable solution.