NANJING, Dec. 13 -- The people of Nanjing observed a minute of silence, and sirens were heard across the city, as China proceeded with its ninth national memorial ceremony Tuesday to mourn the 300,000 victims of the Nanjing Massacre.

Despite the winter chill, thousands of people attended the ceremony in Nanjing, east China's Jiangsu Province, with white flowers pinned to their chests conveying condolences. In front of the crowd, China's national flag flew at half-mast.

At 10:01 a.m., sirens began to blare and the city came to a halt. Drivers in the downtown area stopped their cars and sounded their horns, while pedestrians paused for a minute of silence in remembrance of the victims.

Teenagers read out a declaration calling for peace and citizen representatives struck the Bell of Peace. White doves, symbolizing hope for peace, were released to fly over the square of the Memorial Hall of the Victims in Nanjing Massacre by Japanese Invaders.

The Nanjing Massacre took place when Japanese troops captured the city on Dec. 13, 1937. Over six weeks, they killed more than 300,000 Chinese civilians and unarmed soldiers in one of the most barbaric episodes of World War II.

In 2014, China's top legislature designated Dec. 13 as the national memorial day for the victims of the Nanjing Massacre.

Seven survivors of the massacre passed away this year, reducing the total number of registered survivors to 54. The remaining survivors have an average age of more than 92.

The Chinese government has preserved the survivors' testimonies, recorded in written documents and video footage. These records of the massacre were listed by UNESCO in the Memory of the World Register in 2015.

An exhibition featuring an overseas collection of historical artifacts concerning the massacre, including a camera that captured the atrocities and audio files of Japanese invading soldiers, opened on Tuesday at the memorial hall.

With 453 historical items such as photos and soldiers' logs newly added this year, the museum has so far accumulated more than 192,000 items evidencing this extremely brutal event.

Thirteen descendants of Nanjing Massacre survivors, who were recognized as China's first batch of inheritors of memory of the Nanjing Massacre, attended the memorial ceremony on Tuesday.

They are from the families of ten survivors of the massacre.

"As the survivors get older, their descendants will bear the main responsibility of passing on the historical memories," said Wang Weixing, vice president of the Aid Association of Victims in Nanjing during the War of Aggression against China by Japanese Invaders.

Among the first group of the memory inheritors, Xia Yuan and her son Li Yuhan are both from the family of survivor Xia Shuqin.

"I grew up listening to the war experience of my grandmother. Now she can neither hear nor see clearly. It was her wish that we testify for her and let people know about the crimes committed by the Japanese invaders," said Xia Yuan.

In April this year, Wang Heng, one of the massacre survivors, died at the age of 100. His granddaughter Wang Lian said she helped the centenarian open his online account last year to tell about what he witnessed in the massacre. "I wrote at his dictation. As I told him that the logging had attracted nearly 3,000 followers in less than five days, he looked relieved."