The U.S. Federal Reserve on Monday expanded its purchases of government bonds to an unlimited amount and created programs to buy corporate debt as part of its all-out effort to support the world's largest economy hit by the coronavirus pandemic.

"While great uncertainty remains, it has become clear that our economy will face severe disruptions. Aggressive efforts must be taken across the public and private sectors to limit the losses to jobs and incomes and to promote a swift recovery once the disruptions abate," the Fed said in a statement.

The U.S. central bank said it will buy Treasuries and mortgage-backed securities "in the amounts needed to support smooth market functioning and effective transmission of monetary policy," following up on a $700 billion quantitative easing program it already announced on March 15.

The Fed also decided to launch two new facilities to purchase corporate bonds, including new issues, and said it will support cash-strapped small businesses and consumers through a program facilitating the issuance of asset-backed securities collateralized by student loans, auto loans and credit loans.

Financial markets have been in turmoil in the past weeks, with investors selling stocks and other securities to keep cash at hand in the face of the possible economic downturn.

Economic activities are grinding to a halt in countries hard-hit by the pandemic, including the United States where the number of infections has exceeded 40,000, with over 500 deaths, according to data by Johns Hopkins University.

"The Federal Reserve is using its full range of authorities to provide powerful support for the flow of credit to American families and businesses," the statement said.

The Fed has already held two emergency meetings in March.

In the March 15 meeting, it decided to slash its target range for the federal funds rate by 1 percentage point to 0.00 to 0.25 percent, the lowest level since 2015. It also pledged to buy at least $500 billion in Treasury securities and $200 billion in mortgage-backed securities over the coming months.

The Fed had also resorted to a zero-interest-rate policy and quantitative easing during the 2008 global financial crisis, triggered by the collapse of U.S. investment bank Lehman Brothers Holdings Inc.