Railway workers mourn and train horns wail in Zhengzhou, capital of central China's Henan province, May 19, 2008.

The students of senior 3 at Beichuan Higher Middle School attend a ceremony of resuming classs at a temporary school in quake-hit Mianyang city, southwest China's Sichuan Province, May 19, 2008.

Pupils at the Harbin Jiefang Primary School mourn earthquake dead, May 19, 2008.

Millions of people in China and overseas observed three minutes silence at 2:28 p.m. Monday to mourn thousands of people killed in an earthquake which hit the nation's southwest a week ago.

Chinese President Hu Jintao, top legislator Wu Bangguo, Premier Wen Jiabao, and other top leaders including Jia Qinglin, Li Changchun, Xi Jinping, He Guoqiang and Zhou Yongkang also stood in silence in the central government compound of Zhongnanhai in Beijing.

Across the country, air raid sirens, cars, trains and ship horns wailed in grief as the people fell silent.

Chinese bourses and commodities exchanges also suspended trading for three minutes in remembrance of the earthquake dead. In the Shenzhen bourse, stock traders stood near their office desks for the remembrance. Some of the traders said people have volunteered to buy stocks of Sichuan-based listed companies to show their support.

Cars, motorcycles and bicycles in capital Beijing and other cities stopped in the road and sounded their horns. Pedestrians stood with their heads bowed.

The China Central Television blackened its screen for the three-minute silence. In some of the Chinese embassies overseas, employees wore white paper flowers on their chests while standing in silence in honor of the dead.

"The earthquake took away people's lives, but it will not frighten the brave Chinese people into retreat. We will get over the hardships and a stronger China will have a better future," said He Bin, an police officer of the Anhui Provincial Public Security Department.

After the three-minute tribute, thousands of people at the Tian'anmen square in Beijing, shouting "Brave and strong, China!" and "Brave and Strong, Wenchuan!" with some waving the national flags. Wenchuan county was the epicenter of the 8.0-magnitude quake on May 12.

The three-minute remembrance is part of three-day national mourning for those who died in the earthquake. More than 32,000 people have been confirmed dead and the estimated death toll could top 50,000.

National flags will fly at half mast, public entertainments will be cancelled and the Olympic torch relay suspended during the three-day mourning period.