TOKYO- Japan's Nikkei stock index opened 1.13 percent lower on Wednesday after a mixed session on Wall Street. The benchmark index dropped 94.21 points to 8,229.72 in the first minutes of trading.

US stocks closed mixed overnight, with the Dow Jones Industrial Average rising 0.44 percent at the closing bell in its third straight gain. The tech-heavy Nasdaq fell 0.50 percent while the broad Standard & Poor's 500 index climbed 0.64 percent.

The mixed trading came as the US Federal Reserve announced plans to pump up to 800 billion dollars into the financial system in purchases of mortgage- and asset-backed securities.

The new efforts were aimed at stimulating consumer credit markets that froze up in October while bringing down borrowing costs for the housing market at the center of the economic turmoil.