Air raid sirens, and car, train and ship horns wailed and people stood for three minutes in silence on Monday to mourn the tens of thousands who died in last week's earthquake. [Watch video]

The moment of grief was observed across the vast country of 1.3 billion people at 2:28 pm, exactly a week after the devastating magnitude-8 quake struck Sichuan.

The death toll is estimated to be above 50,000.

The silent tribute was the first of its kind for citizens killed in a natural disaster.

President Hu Jintao and other members of the Standing Committee of the Political Bureau of the Communist Party of China Central Committee, as well as other officials pay a three-minute silent tribute to victims of the quake in the central government compound of Zhongnanhai in Beijing yesterday. The Chinese characters on the banner read: Deep mourning for Wenchuan quake victims. [Xinhua]

Flags were flying at half-mast across the country and all public entertainment has been suspended as the three-day mourning period started.

The Olympic torch relay is also suspended during the period.

From tent cities in Sichuan province to Beijing, cars, motorcycles and bicycles stopped on the road and sounded their horns. Pedestrians stood with their heads bowed.

In Tian'anmen Square, the somber mood quickly turned into a vocal show of patriotism.

Thousands of flag-waving people chanted "Go China Go" and "Rebuild Sichuan", while singing the national anthem.

President Hu Jintao, who just returned from a three-day visit to the quake-hit areas, paid a three-minute silent tribute to victims of the quake in the central government compound of Zhongnanhai in Beijing.