TOKYO (Kyodo) -- Tokyo stocks erased earlier losses and ended higher Tuesday, lifted by some heavyweight technology shares that drew bargain-hunting, despite concerns about escalating tensions in the Middle East.

The 225-issue Nikkei Stock Average ended up 500.77 points, or 0.74 percent, from Monday at 67,743.50. The broader Topix index finished 31.49 points, or 0.79 percent, higher at 4,038.98.

On the top-tier Prime Market, the main gainers were mining, marine transportation and chemical issues.

The U.S. dollar remained firm in the lower 162 yen zone in Tokyo amid growing uncertainty over the U.S.-Iran conflict after President Donald Trump said the previous day his country will resume a blockade of maritime traffic to and from Iran's ports and coastal areas, dealers said.

Stocks swung between positive and negative territory amid mounting concerns over oil supplies after Trump stepped up pressure on Iran, raising fears that shipments through the Strait of Hormuz could be disrupted.

Masahiro Ichikawa, chief market strategist at Sumitomo Mitsui DS Asset Management Co., said, "The (Middle East) outlook remains unfavorable, with uncertainty persisting and higher oil prices keeping investors in an unpredictable situation."

However, as long as the attacks remain limited and negotiations, though difficult, continue under an agreement involving a 60-day ceasefire extension, there is little reason for the market to become overly defensive, Ichikawa added.

Although some heavyweight chip- and artificial intelligence-related shares initially tracked overnight drops in Wall Street, sending the benchmark Nikkei down nearly 1,000 points at one point, they later attracted bargain-hunting after recent declines.