BEIJING, Aug.15 (Xinhua) -- Chinese President Hu Jintao Sunday paid a silent tribute to victims of a massive mudslide in Zhouqu County in northwest China's Gansu Province, as thousands of soldiers continued rescue and relief efforts in the county.

Former President Jiang Zemin and other Chinese leaders, including Wu Bangguo, Wen Jiabao, Jia Qinglin, Li Changchun, Xi Jinping, Li Keqiang, He Guoqiang and Zhou Yongkang, Sunday also lamented the death of the mudslide victims.

The government has declared Sunday a national day of mourning for mudslide victims in Zhouqu County, Gannan Tibetan Autonomous Prefecture. The Aug. 8 disaster left at least 1,200 people dead and 500 missing.

At 10 a.m., thousands of rescuers and villagers stood still on the debris of mudslide at the Dongjie Village in Zhouqu, bowing their heads in commemoration of the dead.

Ceremonies were also held Sunday in Lanzhou, capital of Gansu.

Before and after the ceremonies, rescuers, including troops and medical workers, continued to clear the debris, searching for bodies and spraying disinfectant.

Chinese national flags across the country and at embassies and consulates abroad were lowered to half-mast. All public entertainment was ordered to be suspended.

The Standing Committee of the National People's Congress, the State Council, the Chinese People's Political Consultative Conference, the Central Military Commission, the Supreme People's Procuratorate, the Supreme People's Court and other authorities all flew the national flag at half-mast.

At Tian'anmen Square in downtown Beijing, thousands of people watched the national flag being hoisted to full height and then lowered to half-mast at dawn on Sunday.

Major newspapers, including the People's Daily, the flagship paper of the Communist Party of China, were printed in black and white Sunday. The Beijing Youth Daily and the Beijing News published lengthy editorials to commemorate the victims.

"China has been hit by abnormal weather and frequent natural calamities in the year of 2010.... To confront such unexpected catastrophes, we must have the courage to meet challenges and overcome them," said the editorial in the Beijing Youth Daily.

Soon after midnight, the home pages of Chinese websites turned to black and white.

At an on-line condolences hall on Sina, a major Chinese Internet portal, tens of thousands of people presented virtual chrysanthemums and posted tributes.

"All the pain and hardships we have endured will become impetus for us to move forward. Be strong, Zhouqu!" said an anonymous posting.

Sunday is the seventh day since the mudslide and, according to some Chinese traditions, the seventh day after a death marks the height of the mourning period.

Large-scale national displays of mourning are rare in China.

China observed a three-day national mourning period after the 2008 Sichuan earthquake, and a one-day national mourning period after the Yushu quake on April 14 this year.

On both occasions, the national flag was lowered to half-mast and all public entertainment was suspended.