The mayor of a Japanese city has sparked outrage after playing down a well-documented massacre of civilians in China's former capital more than 70 years ago. An estimated 300,000 people died when Japanese troops invaded the city of Nanjing in China's Jiangsu province in 1937, unleashing a campaign of rape, murder and looting that became known as the Nanjing Massacre. The event was recently portrayed in a movie starring Christian Bale called "The Flowers of War." But earlier this week, Takashi Kawamura, the mayor of Nagoya, told a visiting delegation from Nanjing that he believed only "conventional acts of combat" took place there, not the mass murders and rapes, China's state-run Xinhua news agency reported. He repeated his assertion to Japanese reporters Wednesday.

"It is true that a considerable number of people died in the course of battle. However such a thing as so-called Nanjing Massacre is unlikely to have taken place," he said.

"I have said that without hesitation since people from Chinese Communist Party came to visit us. If they think it is not fact ... they can tell us openly as they want. I am ready to hold an open debate in Nanjing to discuss it."

Kawamura's comments drew fierce criticism on mainstream and social media in China, while Nanjing officials announced they would be suspending ties with Nagoya. The two cities have enjoyed close links since establishing a sister-city relationship in 1978.