NANJING - Former Japanese Prime Minister Yukio Hatoyama on Thursday apologized for Japan's wartime crimes in China and expressed his hope that the tragedy would not be repeated.

Hatoyama made the remarks while touring the Memorial Hall of the Victims of the Nanjing Massacre by Japanese Invaders in the eastern Chinese city of Nanjing.

Hatoyama was the third former Japanese prime minister to visit the memorial after Tomiichi Murayama and Toshiki Kaifu.

During the visit, he often stopped to pay silent tribute to photos or the remains of the victims of the Nanjing Massacre, which was committed by the invading Japanese army in the late 1930s.

Hatoyama nodded as Zhu Chengshan, the memorial's president, told him that it is an undeniable fact, as stated in the verdicts of the Tokyo and Nanjing martial courts, that Japanese invaders killed more than 300,000 people in Nanjing.

"The Japanese government had made it clear when signing the Treaty of San Francisco 1951 that it accepted the verdicts of the Far Eastern International Military Court of Justice and others verdicts regarding its war crimes," Zhu said.

After seeing slogans reading, "To remember the historical lesson of Nanjing, but not for revenge, and to seek eternal world peace for great love," Hatoyama said the words touched him and he hopes that all people will work hard for peace.

"After the tree of peace I planted blossoms and bears fruits, I will come back again," he said at the end of a two-hour visit when he planted a ginkgo tree in a park.

Hatoyama, 66, served as Japan's prime minister between September 2009 and June 2010.