TOKYO, Aug. 21 (Xinhua) -- Tokyo stocks extended their losing streak on Thursday, pressured by weakness in exporters and pharmaceutical stocks.

The benchmark Nikkei stock index, the 225-issue Nikkei Stock Average, fell 278.38 points, or 0.65 percent, from the previous day to close at 42,610.17.

Tokyo shares tracked losses on Wall Street, where the tech-heavy Nasdaq Composite retreated overnight on profit-taking and position adjustments.

In Japan, major chip-related stocks such as Tokyo Electron and SoftBank Group were sold off, while a stronger yen against the U.S. dollar weighed on exporters.

Pharmaceutical shares also dragged the market lower.

The broader Topix index slipped 15.96 points, or 0.52 percent, to 3,082.95.

On the Tokyo Stock Exchange Prime Market, decliners outnumbered gainers 879 to 673, with 68 issues unchanged. ■