TOKYO, Aug 10 (Reuters) - Japanese stocks rose on Tuesday, lifted by strong corporate earnings, but gains were limited by worries about the fast-spreading Delta coronavirus variant.

The Nikkei share average ended the morning session 0.31% higher at 27,905.73, after marking a mid-July peak of 28,128.61 earlier in the session.

The broader Topix rallied 0.56% to 1,940.06, but off its morning high of 1,950.63.

"After the Nikkei hit 28,100, it seems there was a rush to take profits," said a market participant at an asset management company.

"There are still worries about the Delta variant, so sudden rallies are likely to get reined in."

Thinner market conditions may have contributed to volatility. Monday was a national holiday in Japan, and the Obon festival runs from Friday until next Monday, although markets will be open both days.

Mitsui Mining and Smelting Co led gainers on the Nikkei, surging 10.37%, thanks to upbeat earnings posted on Friday.

Smelter Dowa Holdings jumped 6.0% and drugmaker Otsuka Holdings advanced 5.39% following quarterly results.

Conglomerate SoftBank Group added 0.3% ahead of earnings after market close on Tuesday.

On the other side, Sumitomo Metal Mining Co sank 5.12% after earnings disappointed investors.

Sony Group slipped 2.06%, while Nintendo lost 1.97%, making them the two worst performers among the Topix's 30 core names. (Reporting by Tokyo markets team; Editing by Ramakrishnan M.)