The euro extended its biggest weekly gain versus the dollar since January as Group of 20 finance ministers began a two-day meeting to discuss plans to tackle Europe’s debt crisis. The euro rose versus the dollar as Treasury Secretary Timothy F. Geithner said “Europe is clearly” moving to a crisis solution.

The yen fell against the dollar on speculation Japanese authorities will take steps to curtail their currency’s gains. The yen slid 0.6 percent to 77.33 versus the dollar as Dow Jones Newswires reported government officials said they would take new steps against a strong yen as early as next week.

Dollar Index, which tracks the greenback against the currencies of six major U.S. trading partners, decreased today as much as 0.7 percent to 76.508, the lowest level since Sept. 16, on reduced demand for a refuge in the world’s main reserve currency.