WASHINGTON — The Federal Reserve signaled Wednesday that it will keep its key short-term interest rate near zero for the foreseeable future as part of its extraordinary efforts to bolster an economy that is sinking into its worst crisis since the 1930s.

The Fed also said it will keep buying Treasury and mortgage bonds to help keep rates low and ensure companies can continue to lend easily to each other amid a near-paralysis of the economy caused by the coronavirus. It did not specify any amounts or timing for its bond purchases.

“The Federal Reserve is committed to using its full range of tools to support the U.S. economy in this challenging time,” the central bank said in an unusually sweeping declaration.

The pandemic and measures to contain it,” the Fed’s policy statement noted, are “inducing sharp declines in economic activity and a surge in job losses.”

Under Chairman Jerome Powell, the Fed is confronting a deeply perilous moment for an economy that had looked robust just a few months ago. Since the virus struck with full force last month, widespread business shutdowns have caused roughly 30 million workers to lose jobs. As layoffs mount, retail sales are sinking, along with manufacturing, construction, home sales and consumer confidence.

The Fed also raised concerns about slowing inflation, likely to sink further below its 2 percent target level in the coming months.