WASHINGTON (AP) -- The Federal Reserve said Wednesday that it plans to keep interest rates ultra-low even after unemployment falls close to a normal level -- which it thinks could take three more years.

As long as expected inflation remains tame, the Fed said it could keep its key short-term rate near zero even after unemployment falls below 6.5 percent. Unemployment is now 7.7 percent.

For the first time, the Fed is making clear to investors and consumers that it will link its actions to specific economic markers. Previously the Fed had said only that it expects to keep the rate low until at least mid-2015.

Analysts said the Fed's new guidance will make it easier for companies, investors and consumers to make financial decisions because they will have a clearer grasp of when borrowing costs will begin to rise.

"This approach is superior" to setting a timetable for a possible rate increase, Chairman Ben Bernanke said at a news conference after the Fed held a two-day policy meeting and issued a statement. "It is more transparent and will allow the markets to respond quickly and promptly to changes" in the Fed's economic outlook.

Though the Fed's low interest-rate policies are intended to boost borrowing, spending and stock prices, they also hurt millions of retirees and others who depend on income from savings.

Bernanke made clear that even after unemployment falls below 6.5 percent, the Fed might decide that it needs to keep stimulating the economy. Other economic factors will also shape its policy decisions, he said.

"The Fed has become more explicit and more transparent," said Steven Wood, chief economist at Insight Economics. "This should provide the markets with much more clarity around monetary policy action in the upcoming year."

In its statement, the Fed said it will also keep spending $85 billion a month on bond purchases to drive down long-term borrowing costs and stimulate economic growth.

The Fed will spend $45 billion a month on long-term Treasury purchases to replace a previous bond-purchase program of an equal size.

And it will keep buying $40 billion a month in mortgage bonds.