In the first 15 minutes of trading, the 225-issue Nikkei Stock Average lost 33.69 points, or 0.34 percent, to 9,918.13 from Monday's two- month closing low. The broader Topix index of all First Section issues on the Tokyo Stock Exchange was down 2.70 points, or 0.31 percent, to 880.31. The Second Section also lost ground.

By sector, pulp and paper saw the largest percentage decrease, followed by electricity and gas, and pharmaceuticals. The banking, sea transport and auto sectors were among the major gainers.

Stocks opened lower in Tokyo after investors continued to shy away from equities, considered more risky than assets such as bonds, on Wall Street amid heightened worries about the debt crisis in Greece, Portugal and Spain. Foreign investors account for about 50 percent of trading on the Tokyo market.

But losses were gradually trimmed with support from dip-buying after the Nikkei lost about 1 percent the previous day to close below 10,000 for the first time since December, brokers said.