Mourners visit the scene of the fire on Wednesday.[China Daily]

The death toll from Monday's high-rise apartment building fire in Shanghai has risen to 58 and police have detained four more people in connection to the blaze, local authorities said Friday.

The identities of 26 of the 58 victims have been confirmed, with 22 of them male and 36 female, the Public Security Bureau of Shanghai said.

Relatives of 56 residents of the building have told police their loved ones are missing, police said, adding that some of them may have died in the fire.

Police Friday detained four more people in connection to the fire, bringing the total number detained to 12.

They include managers of Shanghai Jing'an District Construction Corp., the chief contractor of the renovation project, and managers from the project's two sub-contractors - Shanghai Jiayi Decoration Corp. and Shanghai Dimu Property Managment Co. Ltd. Shanghai Dimu was in charge of the project's scaffolding.

Staff from Shanghai Jing'an District Construction Projects Supervision Co. Ltd., the project's supervisor, were also among those detained.

The blaze erupted Monday afternoon after sparks form welding set nylon netting and scaffolding alight.

Luo Lin, head of the State Administration of Work Safety, has blamed the tragedy on unlicensed welders, illegal multi-layered sub-contracting and poor management.

Shanghai ordered strict fire safety inspections across the city soon after the accident. All construction sites in the city were ordered to suspend work for two hours Friday morning to check for fire risks.