TOKYO (Kyodo) -- The Nikkei stock index briefly plunged over 3 percent early Friday, tracking overnight Wall Street losses amid overheating concerns regarding semiconductor-related shares despite a favorable earnings result released the previous day.

In the first 15 minutes of trading, the 225-issue Nikkei Stock Average fell 1,955.83 points, or 2.93 percent, from Thursday to 64,879.71. The broader Topix index was down 71.88 points, or 1.78 percent, at 3,956.91.

On the top-tier Prime Market, the main decliners were nonferrous metal, electric appliance and machinery issues.

At 9 a.m., the U.S. dollar fetched 162.38-39 yen compared with 162.32-42 yen in New York and 162.08-09 yen in Tokyo at 5 p.m. Thursday.

The euro was quoted at $1.1445-1445 and 185.83-87 yen against $1.1438-1448 and 185.73-83 yen in New York and $1.1469-1470 and 185.90-94 yen in Tokyo late Thursday afternoon.