In its latest measure to combat the economic fallout from the coronarvirus pandemic, the Fed said Tuesday it was establishing a temporary repurchase agreement facility to allow foreign central banks to swap any Treasury securities they hold for cash. That's yet another step beyond the actions it took in the 2008 financial crisis.

"To the Federal Reserve's credit, it is playing the role of central banker to the world rather than denying it and trying to ward it off," said former Fed official Ted Truman, who is now a senior fellow at the Peterson Institute for International Economics in Washington.

The Fed is trying to prevent a liquidity squeeze amid a worldwide rush into dollars, as the virus wreaks havoc on a global economy that is heavily dependent on the greenback as its linchpin.

"A lot of borrowing and commerce and investing is done in dollars," Julia Coronado, founding partner of MacroPolicy Perspectives in New York and a former Fed economist, said in an interview on Bloomberg Radio. "When you have a dollar crunch, it can turn a recession or contraction in activity into a financial crisis very quickly because the dollar shortage can trigger defaults and deleveraging."