But Trump praised the Fed's action Sunday. “It makes me very happy, and I want to congratulate the Federal Reserve,” he told reporters at the White House. “That’s really good news, that’s really great for our country. … I think people in the market should be very thrilled.”

The central bank’s emergency actions are among the federal government’s first responses to cushion the economy from what is expected to be a severe blow from the coronavirus outbreak.

The House early Saturday passed an aid package for workers, and the Senate is expected to consider it in the coming days. Trump administration officials also worked throughout the weekend to craft rescue packages for key sectors, such as airlines and hospitality, that are already getting crushed by plunging demand.

But many investors were looking to the Fed, which played a lead role in boosting the economy during the crippling 2008 crisis. The initial response from overseas wasn't promising, as stock futures fell more than 1,000 points after the centtral bank announcement, suggesting that U.S. markets may open lower on Monday.

The Fed said it will increase its holdings of U.S. government bonds by at least $500 billion and its holdings of mortgage-backed securities by at least $200 billion over the next few months, steps that will lower the cost of longer-term debt and support the housing market, much like they did during and after the 2008 financial crisis.

Powell said in a broadcast teleconference with reporters that the asset purchases are aimed at making sure key markets, such for U.S. government bonds and the mortgage market, are functioning properly.

The U.S. government bond market “plays an important role in allowing households and firms to earn a safe return and manage their risks,” the Fed chief said. “When stresses arise in the Treasury market, they can reverberate through the entire financial system and the economy.”

He also pointed to economic pain that has already showed up in key sectors and general unease in markets. “The cost of credit has risen for all but the strongest borrowers, and stock markets around the world are down sharply,” he said.