Treasury Secretary Janet Yellen said interest rates may have to increase somewhat in order to keep the U.S. economy from overheating.

In an interview with the Atlantic that was recorded Monday and aired Tuesday, the Treasury chief said, “It may be that interest rates will have to rise somewhat to make sure that our economy doesn’t overheat, even though the additional spending is relatively small relative to the size of the economy.”

Yellen was discussing the Biden administration’s $2.3 trillion infrastructure proposal and its $1.8 trillion American Families Plan. She acknowledged that those proposals have “high price tags,” but stressed that they are long-term programs.

If approved by Congress, those plans would come on top of the $1.9 trillion COVID relief bill President Joe Biden signed in March.

Later Monday at a Wall Street Journal event, Yellen stressed she was not “predicting or recommending” rate increases.

“If anybody appreciates the independence of the Fed, I think that person is me,” Yellen said.

The Treasury Secretary said she was simply saying the Fed could be counted on to meet its goals of full employment and price stability.

“I don’t anticipate that inflation is going to be a problem, but it is something that we’re watching very carefully,” Yellen said.

“I don’t think there is going to be an inflation problem if there is the Fed, I am certain, will be counted on to address them,” she said.

On Sunday, Yellen said that Biden’s proposed spending on infrastructure and families would not fuel inflation, because the plans would be phased in gradually over 10 years.

On Monday, Senate Republican Leader Mitch McConnell said Democrats should expect “zero” support from his party for Biden’s new big-ticket infrastructure and social spending proposals. Biden’s party faces a variety of choices on how to proceed, including whether to use a process called budget reconciliation, which would allow Democrats to pass a bill without GOP votes in the Senate.

Last week, the Federal Reserve after its latest meeting stuck to its strategy of helping the U.S. economy with ultra-low interest rates even as it saw broad signs of faster growth. The central bank held a key short-term interest rate near zero and maintained monthly purchases of $120 billion in Treasury and mortgage-backed bonds.

Chairman Jerome Powell said the Fed would stay the course until the economy strengthened even further and coronavirus cases fell sharply.

U.S. stocks DJIA, +0.41% SPX, +0.73% COMP, +1.31% deepened their losses in the wake of the interest-rate comments by Yellen, a former head of the Federal Reserve. The Dow Jones Industrial Average managed to finish the day up, but other indexes ended lower Tuesday, with the Nasdaq suffering its worst one-day fall since March.