TOKYO (Kyodo) -- Tokyo stocks retreated Tuesday, with the Nikkei stock index closing at a six-month low after diving more than 2 percent at one point due to concerns that Japan may not be immune to U.S. President Donald Trump's tariff policies.

The 225-issue Nikkei Stock Average ended down 235.16 points, or 0.64 percent, from Monday at 36,793.11. The broader Topix index finished 30.04 points, or 1.11 percent, lower at 2,670.72.

On the top-tier Prime Market, decliners were led by nonferrous metal, securities house and service issues.

The U.S. dollar briefly weakened to the mid-146 yen zone in Tokyo, as the safe-haven yen was bought on uncertainty about the outlook for the U.S. economy amid Trump's erratic tariff threats against his country's closest trading partners such as Canada, dealers said.

At 5 p.m., the dollar fetched 146.91-93 yen compared with 147.23-33 yen in New York and 147.58-60 yen in Tokyo at 5 p.m. Monday.

The euro was quoted at $1.0889-0891 and 159.98-160.02 yen against $1.0832-0842 and 159.47-57 yen in New York and $1.0822-0824 and 159.72-76 yen in Tokyo late Monday afternoon.

The yield on the benchmark 10-year Japanese government bond fell 0.070 percentage point from Monday's close to 1.505 percent, briefly declining to 1.490 percent, as the debt, also considered a low-risk asset, was bought on negativity about the prospects for the world's largest economy.

Tokyo stocks dropped almost across the board in the morning, sending the Nikkei index below the 36,000 line for the first time since last September, after Trump said in a TV interview aired Sunday that there will be "a period of transition" when asked about the possibility of a U.S. recession.

Stocks also extended losses as Japanese trade minister Yoji Muto failed to win assurances from U.S. officials in Washington that Japan would be given dispensation from Trump's planned new tariffs on steel, automobiles and other imports.

"It seems to have become difficult for Japan to be exempted from (the 25 percent) tariffs on steel and aluminum imports even though trade minister Muto has worked hard...and I think that affected (investor sentiment)," said Seiichi Suzuki, chief equity market analyst at Tokai Tokyo Intelligence Laboratory Co.

After dropping over 1,000 points, or more than 2 percent, the Nikkei trimmed losses to close at its highest point for the day, as sentiment was supported by gains on U.S. futures, brokers said.