WASHINGTON—Federal Reserve Chair Jerome Powell warned Thursday that Russia’s invasion of Ukraine, which has already driven up oil prices, will likely further magnify the high inflation that has engulfed the U.S. economy. At the same time, Powell said he is committed to doing whatever it will take to slow inflation, underscoring the Fed’s high-risk challenge in raising interest rates enough to stem price increases without tipping the economy into another recession. The Fed chair, addressing the Senate Banking Committee on his second day of semiannual testimony to Congress on interest rate policies, stressed his belief that the economy is strong enough to withstand higher borrowing costs. His expression of confidence echoed his testimony Wednesday that the Fed can engineer a “soft landing” in which the economy would slow enough to ease inflation even while hiring and growth remain healthy. “Commodity prices have moved up—energy prices, in particular,” Powell said when …