Former Prime Minister Yasuo Fukuda on Sunday visited a memorial hall dedicated to victims of the 1937 massacre committed by Japanese troops against civilians in the city now known as Nanjing, Chinese media reported Monday.

Fukuda became the fourth former prime minister to visit the memorial hall in the eastern China city, after Toshiki Kaifu, Tomiichi Murayama and Yukio Hatoyama.

After offering flowers and a silent prayer at the hall, Fukuda was quoted as telling reporters that peace is of utmost importance and that the tragedy of war must not be repeated ever again.

He also said it is necessary to face up to what already happened, adding, “Japanese people need to visit the memorial hall and understand the history,” according to the media reports.

The scale of killings of civilians and soldiers by Japanese troops during and in the weeks after the seizure of Nanjing, then the capital of the Nationalist Chinese government of Chiang Kai-shek, has been the subject of much debate.

China claims the Japanese army slaughtered more than 300,000 people in the city, while estimates from Japanese historians on the death toll of Chinese civilians and soldiers vary from tens of thousands to 200,000.