WASHINGTON – The Federal Reserve, acting in coordination with other global central banking authorities, cut a key U.S. interest rate by half a percentage point Wednesday to steady a teetering economy.

The Fed reduced its key rate from 2 percent to 1.5 percent.

In Europe, which also has been hard hit by the financial crisis, the Bank of England cut its rate by half a point to 4.5 percent, while the European Central Bank sliced its rate to 3.75 percent.

Other central banks also taking part include the banks of Canada, Sweden, and Switzerland.

China also cut its key interest rates Wednesday for a second time in less than one month to stimulate slowing economic growth amid the global credit crisis.

Fed Chairman Ben Bernanke and his colleagues ratcheted down their key rate by 0.5 percentage point to 1.5 percent. The action revives the central bank’s rate-cutting campaign which had been halted in June out of concerns that those low rates would worsen inflation. Since then, however, economic and financial conditions have dangerously deteriorated, forcing the Fed to reverse course.

The fact that the Fed felt it couldn’t wait until its regularly scheduled meeting on Oct. 28-29, underscored the urgency of the situation.