China on Monday censured an Japanese official's criticism of recent remarks by President Xi on his European tour.

"We are strongly dissatisfied and opposed to the Japanese side's irrational attitude," said Foreign Ministry spokesman Hong Lei, commenting the words of Yoshihide Suga, chief secretary of Japan's Cabinet.

Suga described as "unproductive" Xi's comments on Japan's history and the Nanjing Massacre while the Chinese President addressed a think tank in Berlin.

Xi told his German audience that the Japanese invasion, which caused more than 35 million Chinese casualties, still held "bitterly painful memories" for the Chinese people.

"The invasion, including the Nanjing Massacre, is an irrefutable fact. President Xi mentioned this period in his speech to emphasize the importance of maintaining justice and peace, preventing the repeat of historical tragedies and working for a better future," Hong told a regular press briefing.

Japan invaded China in 1937 and on Dec. 13, 1937, started a massacre in Nanjing, then capital of China. More than 300,000 Chinese people lost their lives in the 40 days that followed.

Hong noted that denying and embellishing history was becoming more frequent in Japan. All peace loving people, he said, should be highly concerned and on their guard.

Hong urged Japan to regain trust of their neighbors and the international community at large by adopting "a correct understanding and attitude" towards its history.