Yu Zhengsheng (center), secretary of the Shanghai municipal committee of the Communist Party of China, and Han Zheng (second right), mayor of Shanghai, attend a memorial ceremony for the 58 victims of the high-rise blaze near the site of the Nov 15 tragedy. [Photo/Xinhua]

Luo Lin, head of the State Administration of Work Safety, who led the investigation into the blaze, has blamed the tragedy on unlicensed welders, illegal multi-layered sub-contracting and lax management.

A total of 12 people have been detained, including project supervisors, building construction managers and unlicensed workers.

Residents who escaped from the fire are either staying with family, friends or in temporary shelters. Those in temporary shelters will be given accommodation for as long as necessary, Gong Deqing, Party chief of Jing'an district, where the building is located, was quoted as having said by Beijing News.

The fire has raised concerns over the efforts by some local governments to meet energy efficiency targets by adding a thermal layer of insulation to the outside of buildings - the project the welders were working on when the fire broke out.

The insulation material was supposed to be flame resistant, but it caught fire almost immediately.

Beijing has ordered a halt to similar projects, pending reviews and "rectification" of any problems.

AP and Reuters contributed to this story.