President Xi Jinping said Saturday that no one can deny the Nanjing Massacre, as China for the first time held a national day of remembrance for the Japanese military rampage that Beijing says killed 300,000 people.

State media estimated 10,000 people attended a ceremony in Nanjing to mark the 77th anniversary of the massacre, including ageing survivors -- some in their 90s -- of the Japanese invasion of the eastern city on December 13, 1937.

The crowd sang a boisterous rendition of China's national anthem at the ceremony broadcast live on CCTV state television, followed by a moment of silence, as a siren symbolising grief blared and the Chinese flag flew at half-mast under clear skies.

"Anyone who tries to deny the massacre will not be allowed by history, the souls of the 300,000 deceased victims, 1.3 billion Chinese people and all people loving peace and justice in the world," Xi said in a speech at the ceremony, according to the state-run Xinhua news agency.

Zhang Dejiang, chairman of the NPC and foreign minister Wang Yi were among Chinese dignitaries who attended

Before the ceremony, CCTV showed black and white still and filmed images from the period, including scenes of Japanese soldiers occupying Nanjing and photos of dead Chinese, some in the streets and some along a river bank.

Xi also appeared to hold out an olive branch to Japan, emphasising the need for Chinese and Japanese to live in friendship, stressing that it was "militarists" who were responsible for the massacre.

"We should not bear hatred against an entire nation just because a small minority of militarists launched aggressive wars," Xi said, according to Xinhua.

"The responsibilities for war crimes lie with a few militarists, but not the people," he added, though also emphasised that "severe crimes committed by aggressors" cannot be forgotten.

Later 3,000 doves symbolising peace were released into the skies in memory of the victims, Xinhua said.

In February, China's National People's Congress, the country's Communist Party-controlled legislature, made the anniversary of the Nanjing Massacre an official day of remembrance -- along with September 3 to mark the country's victory against Japan in 1945 -- as tensions with Japan over a maritime territorial dispute and rows over history intensified.

Japan and the People's Republic of China established diplomatic relations in 1972. But ties have been strained by the row over uninhabited islands in the East China Sea and nationalist views and actions by Japanese politicians, including visits to Tokyo's Yasukuni Shrine, which commemorates Japan's war dead including convicted war criminals from World War II.

Last month, however, Xi and Japanese Prime Minister Shinzo Abe, who provoked China's ire by visiting Yasukuni last December, held a strained first formal summit in Beijing on the sidelines of the annual APEC leaders' meeting in a bid to improve bilateral relations.

The "Rape of Nanking" is an exceptionally sensitive issue in the often-tense relations between Japan and China, with Beijing charging that Tokyo has failed to atone for the atrocity.

The Japanese military invaded China in the 1930s and the two countries fought a full-scale war from 1937 to 1945 that ended with Japan's defeat in World War II.

China says 300,000 people died in a six-week spree of killing, rape and destruction after the Japanese military entered Nanjing, although some respected foreign academics put the number lower.

China historian Jonathan Spence, for example, estimates that 42,000 soldiers and citizens were killed and 20,000 women raped, many of whom later died.

In Japan, however, some question that view. In February, a senior executive at Japan's publicly-funded TV broadcaster NHK denied the massacre, reportedly dismissing accounts of it as "propaganda".

Japan's official position is that "the killing of a large number of noncombatants, looting and other acts occurred", though adds "it is difficult to determine" the correct number of victims.

In commentary ahead of the ceremony, Xinhua accused Japan of "attempting to whitewash" and "gloss over its wartime atrocities".