Beijing, China (CNN) -- Mourners lined up Sunday to lay flowers in front of a charred 28-story high-rise in Shanghai, China, where a fire killed at least 58 people last week, witnesses told CNN.
Amid tight security, thousands gathered at the site Sunday morning.
"There are tons of people here," said Peijin Chen, a freelance photographer who lives across the street from the building. "Police have put up new barriers for crowd control."
"A flyer saying 'Don't cry, Shanghai' was being handed out," he added. "But an old man asked me how could we not cry with all those dead."
Under the watchful eyes of police officers, mourners left a sea of yellow and white chrysanthemums around the building and on the street, as an orchestra of volunteer musicians played music nearby.
A photo circulating on Chinese websites shows a note left along with a stuffed bear for the youngest victim, a 1-year-old baby, who reportedly died in the fire with his grandmother.
"Baby, hold tight to Grandma's hand," the note read. "May this teddy bear accompany you to Heaven, where there is no disaster."
Authorities have detained 12 suspects related to the blaze, and blamed unqualified welders for violating safety rules and starting the fire. Chinese media reports have since alleged close connections between the main contractor and the local district government.
The building, which housed 150 families, was under renovation when it went up in flames. State media reported the blaze broke out on the north side of the 10th floor when a scaffolding caught fire, and flames then spread to the building.
"The fire became so big because the scaffolding contained a great amount of flammable materials," Zhu Zhixiang, a Shanghai firefighting official told state broadcaster CCTV last week. "Heavy wind at the time was another factor."
Firefighters rescued more than 100 residents from the burning building, and local officials have informed them they will have to seek housing elsewhere for the foreseeable future.