ZURICH (Reuters) - Debt levels in the United States and Europe are a risk for international financial stability and for Switzerland, Swiss Finance Minister Karin Keller-Sutter said in a newspaper interview published on Saturday.

In an interview with Swiss daily Blick, Keller-Sutter extolled Switzerland's "disciplined" finances, which she said had enabled the country to deal with the economic challenges posed by the COVID-19 pandemic and Russia's invasion of Ukraine.

By contrast, other countries are "so indebted they're hardly able to act any more", she said, giving France as an example.

"Or take a look at America. That's a time bomb. The mini-crash on the stock markets at the start of August was a warning shot," the minister was quoted as saying.

"It was an expression of investors' fear of a recession. Debt levels in the U.S. and Europe are a risk to international financial stability and a risk for Switzerland," she added.

Keller-Sutter also discussed a government proposal to make Swiss bank UBS hold more capital in the wake of its acquisition of former rival Credit Suisse following its collapse last year.

She defended the additional capital requirements as necessary to protect Switzerland from another banking meltdown.

UBS CEO Sergio Ermotti has criticised the proposal, and she was asked whether she was in touch with him about it, saying:

"No, I haven't been in contact with him any more. This is now a normal political process."

The paper also asked what she thought about speculation that UBS could shift its headquarters abroad if it felt conditions in Switzerland were no longer right for it.

"The Federal Council (cabinet) believes it's good for the economy to have a large Swiss bank. But the bank must decide for itself how it wants to position itself."

UBS has said repeatedly it is committed to Switzerland.