BEIJING -- The lawmakers are mulling making December 13 a national memorial day to commemorate those killed by Japanese aggressors during the Nanjing Massacre in the 1930s.

The draft decision will be discussed at the bi-monthly session of the Standing Committee of the National People's Congress (NPC) which runs from Tuesday through Thursday.

Japanese troops started the massacre in Nanjing on Dec. 13, 1937, killing more than 300,000 people in the following 40-odd days.

As a flagrant violation of international laws, the atrocity was tried by the International Military Tribunal for the Far East and the Nanjing War Crimes Tribunal, which have already rendered a verdict based on irrefutable evidence, said Li Shishi, director of the Legislative Affairs Commission of the NPC Standing Committee.

"It is extremely necessary to set a national memorial day for the Nanjing Massacre victims and hold public memorial service and other activities on the national level," Li said.

The draft decision was made to mourn the victims of the massacre and all those killed during the Japanese aggression against China, exposing the war crimes of Japanese invaders, he said.

The occasion is expected to serve as a reminder of calamities the war caused for Chinese people and the world, and as an expression of the Chinese people's stance of combating aggression and safeguarding human dignity and world peace, according to the official.

Lawmakers, political advisors and people from all walks of life have repeatedly proposed setting Dec. 13 the national memorial day for the victims, Li said.