Washington, D.C. ? With the country sinking deeper into recession, the Federal Reserve launched a bold $1.2 trillion effort Wednesday to lower rates on mortgages and other consumer debt, spur spending and revive the economy.

To do so, the Fed will spend up to $300 billion to buy long-term government bonds and an additional $750 billion in mortgage-backed securities guaranteed by Fannie Mae and Freddie Mac.

Fed Chairman Ben Bernanke and his colleagues wrapped a two-day meeting by leaving a key short-term bank lending rate at a record low of between zero and 0.25 percent. Economists predict the Fed will hold the rate in that zone for the rest of this year and for most — if not all — of next year.

The decision to hold rates near zero was widely expected. But the Fed’s plan to buy government bonds and the sheer amount — $1.2 trillion — of the extra money to be pumped into the U.S. economy was a surprise.

“The Fed is clearly ready, willing and able to be the ATM for the credit markets,” said Terry Connelly, dean of Golden Gate University’s Ageno School of Business in San Francisco.