More than 6.6 million Americans filed jobless claims in the week ending April 4, the Department of Labor said.
The number of people seeking unemployment benefits has surged for a third week as the economic toll tied to the coronavirus pandemic intensifies.
To shore up the economy, the Fed said it would unleash an additional $2.3 trillion in lending.
The deepening economic crisis comes as the number of Covid-19 cases in the US soars to more than 430,000.
Over the last three weeks, more than 16 million people have made unemployment claims, as restrictions on activity to help contain the virus force most businesses to close and put about 95% of Americans on some form of lockdown.
Labor Secretary Eugene Scalia said: “Today’s report continues to reflect the personal sacrifice being made by America’s workers and their families to slow the spread of the coronavirus.”
The surging unemployment rate is a stark reversal for the world’s biggest economy where the unemployment rate had been hovering around 3.5%. Economists now expect that rate has hit the double digits.
The crisis has prompted dramatic government relief efforts.
The Fed programs on April 9, which include loans to local governments, are the latest actions by the central bank, which has also slashed interest rates, eased banking regulations and announced other programs aimed at supporting home loans, currency markets and small businesses.
Fed Chairman Jerome Powell said the bank is using its emergency powers to “unprecedented extent”.
He said: “We will continue to use these powers forcefully, proactively and aggressively until we’re solidly on the way to recovery.”
The Congress has also passed a roughly $2 trillion rescue bill, which funds direct payment for households, assistance for businesses and increased unemployment benefits. Lawmakers are now discussing further relief.
However, the number of people and companies seeking assistance has overwhelmed rescue efforts so far.