Ms. Lagarde, in office fewer than five months, was under intense pressure to take actionto contain the economic side effects of the virus outbreak.

Economists have largely stopped arguing about whether there will be a recession in the eurozone and are instead debating how long it will last. “Dramatic declines in global growth have to be expected,” the Kiel Institute for the World Economy, an influential German research organization, predicted on Thursday.

But the European Central Bank had less room to maneuver than its peers. It had already cut interest rates almost as low as they could go in an unsuccessful attempt to push up inflation to the level considered optimal for growth.

Some analysts argued that the latest actions were a de facto interest rate cut, even though official benchmark rates stayed the same.

One measure announced Thursday would allow commercial banks to borrow as much money as they want for three months at a negative interest rate, meaning they don’t have to pay all of the money back.

In addition, if banks promise to lend central bank funds to their customers and meet certain other conditions, they will be able to borrow money for three years at a negative interest rate of 0.75 percent.

“Although the Governing Council does not see material signs of strains in money markets or liquidity shortages in the banking system, these operations will provide an effective backstop in case of need,” the central bank said in a statement.