In an announcement before the start of trading on the Tokyo Stock Exchange, the Fed lowered its so-called discount rate by a quarter of a percentage point to 3.25 percent. The central bank also approved the financing of JPMorgan Chase & Co.'s purchase of Bear Stearns Cos., including support for as much as $30 billion of Bear's assets.

Fed Chairman Ben S. Bernanke is stepping up efforts to keep strains in financial markets from spiraling into a full-blown meltdown. Last week the central bank agreed to emergency loans to a non-bank, Bear Stearns, for the first time since the 1960s. Fed officials also announced a program to swap $200 billion in Treasuries for debt including mortgage-backed securities.

The dollar tumbled to a 12-year low against the yen after the announcement and Treasury notes rallied in Asian trading. The Nikkei 225 Stock Average lost 3.1 percent at 9:35 a.m. in Tokyo.

From tomorrow, primary dealers will be able to borrow at the rate under a new lending facility, to be in place for at least six months, the Fed said. The Fed will accept a ``broad range'' of investment-grade collateral.

Investors expect the Fed to lower its benchmark rate by as much as a full percentage point, to 2 percent, when policy makers meet March 18. That would exceed the 0.75-point emergency reduction on Jan. 22, which is the largest Since the overnight interbank lending rate became the main tool of monetary policy about two decades ago.