TOKYO (Kyodo) -- Tokyo stocks ended higher Thursday as technology issues rose on hopes for robust investment and a weaker yen lifted exporters, but a cautious mood prevailed amid uncertainty over U.S. tariff policy.

The 225-issue Nikkei Stock Average ended up 312.62 points, or 0.79 percent, from Wednesday at 39,958.87. The broader Topix index finished 14.55 points, or 0.53 percent, higher at 2,751.74.

On the top-tier Prime Market, the main gainers were nonferrous metal, machinery and real estate shares.

The U.S. dollar briefly rose to the upper 156 yen range in Tokyo, as long-term U.S. Treasury yields climbed on speculation about a potential resurgence of inflation in the United States due to President Donald Trump's tariff plans, dealers said.

At 5 p.m., the dollar fetched 156.60-62 yen compared with 156.46-56 yen in New York and 156.04-06 yen in Tokyo at 5 p.m. Wednesday.

The euro was quoted at $1.0400-0401 and 162.87-91 yen against $1.0404-0414 and 162.90-163.00 yen in New York, and $1.0411-0412 and 162.46-50 yen in Tokyo late Wednesday afternoon.

The yield on the benchmark 10-year Japanese government bond rose 0.010 percentage point from Wednesday's close to 1.205 percent, tracking the upward trend in long-term U.S. Treasury yields.

On the stock market, heavyweight technology shares led advances, pushing the Nikkei to briefly reclaim the 40,000 line for the first time in around two weeks after gains by their U.S. counterparts overnight.

The positive sentiment was fueled by a continued surge in SoftBank Group after Trump announced earlier this week a $500 billion U.S. artificial intelligence investment project involving the Japanese technology giant, analysts said.

While the yen's depreciation also supported exporter shares, uncertainty over potential U.S. tariffs weighed on the market, with "the specifics of the Feb. 1 tariff measures (on Mexico, Canada and China) a key concern for investors," said Maki Sawada, a strategist in the Investment Content Department of Nomura Securities Co.

A wait-and-see mood also prevailed ahead of the outcome of the Bank of Japan's two-day meeting through Friday, Sawada added. The central bank is widely expected to raise its policy rate to 0.5 percent from the current 0.25 percent.