TOKYO (Kyodo) -- Tokyo stocks fell sharply Friday, with the key Nikkei index briefly sliding over 2 percent, as investors locked in gains in heavyweight technology shares following losses by their U.S. counterparts.

The 225-issue Nikkei Stock Average ended down 905.30 points, or 1.77 percent, from Thursday at 50,376.53. The broader Topix index finished 21.91 points, or 0.65 percent, lower at 3,359.81.

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

The U.S. dollar briefly weakened to the lower 154 yen zone in Tokyo, as the yen, seen as a safe-haven asset, was bought amid steep declines in Tokyo stocks, dealers said.

At 5 p.m., the dollar fetched 154.67-69 yen compared with 154.51-61 yen in New York and 154.71-73 yen in Tokyo at 5 p.m. Thursday.

The euro was quoted at $1.1632-1634 and 179.92-96 yen against $1.1629-1639 and 179.76-86 yen in New York and $1.1611-1612 and 179.64-68 yen in Tokyo late Thursday afternoon.

The yield on the benchmark 10-year Japanese government bond briefly rose to 1.705 percent, its highest level since June 2008, as the debt was sold on concerns that Prime Minister Sanae Takaichi's economic policy, with aggressive fiscal spending, may worsen Japan's fiscal health.

It ended at 1.700 percent, up 0.010 percentage point from Thursday's close.

The higher yield was also driven by a rise in U.S. Treasury yields after expectations that the U.S. Federal Reserve will cut interest rates again next month receded.

On the stock market, semiconductor and artificial intelligence-related issues tracked drops on Wall Street amid concerns over recent overheating and speculation that the pace of future rate cuts by the Fed may slow, brokers said.

"There was no particular bad news" that led to Friday's declines, said Maki Sawada, strategist in the Investment Content Department of Nomura Securities Co.

"Investors took profits ahead of the weekend and the release of (U.S. chip giant) Nvidia Corp.'s earnings results next week, amid lingering caution about whether tech companies can yield sufficient returns on their massive investments in AI," she said.

Meanwhile, some investors bought shares of Japanese companies that revised their earnings projections upward, including department store chain operator Isetan Mitsukoshi Holdings.