China is marking the fifth anniversary of the Sichuan earthquake, which killed more than 80,000 people.

Activities marking the anniversary began on Sunday with a one-minute silence in remembrance of the victims. Flowers were also laid before a monument in old Beichuan county.

The 8.0 magnitude earthquake struck the southwestern province of Sichuan on the afternoon of May 12, 2008, with its epicentre at Wenchuan county.

Another 4.45 million were hurt in the country's worst quake in more than three decades.

The People's Daily, the ruling Communist Party's mouthpiece, called the earthquake a "grave catastrophe" but said the recovery was a symbol of China's strength.

"In less than three years, the Wenchuan disaster zone has completed the task of reconstruction with impressive speed," the paper said in a front-page commentary.

"To achieve a new victory of building a prosperous society, this is the best way to commemorate the fifth anniversary of the Wenchuan earthquake."

'Tofu-built' projects

But as survivors carry on with their lives, questions remain over the thousands of children who died as their schools collapsed.

The China Daily newspaper said the country had learned lessons from the disaster as schools and hospitals were able to withstand another quake in the region last month.

But outspoken internet commentators focused attention on the children who died.

"It's the fifth anniversary of the earthquake as well as Mother's Day. Hard to forget those young faces lying under the school buildings," said Fengguo De Wuhou 1117 on a microblog.

"Five years and the promise to thoroughly investigate the 'tofu-built' projects in the quake area still lingers around the ears," said the posting, using a Chinese phrase for shoddy construction.

In pictures: China remembers Sichuan quake

About 7,000 schools were badly damaged in the earthquake, triggering accusations of poor construction and corruption, especially as some other buildings nearby remained standing.

Calls for transparency from the government on how many students were killed led to beatings and arrests of activists, including dissident artist Ai Weiwei.

Ai on Sunday tweeted a link to his work "Remembrance", voice recordings of people reading the names of students who died in the earthquake, which he puts at more than 5,000.

The artist was badly beaten by police when he tried to testify in support of activist Tan Zuoren, who had investigated the collapse of the school buildings.

Source: Al Jazeera and agencies