The General Administration of Customs stressed on Thursday it is illegal for local governments or companies to ask custom authorities across China to seize or temporarily detain legally imported materials for epidemic prevention and control.

The GAC, one of China's key border agencies, conducted an inspection in 42 customs districts nationwide. The GAC found these districts have performed their duties in accordance with the law and provided timely customs clearance for imported epidemic prevention and control materials, the GAC said in a statement on Thursday.

However, the GAC noticed a few local governments and companies have requested local customs to seize or temporarily detain legally imported materials for epidemic prevention and control with various excuses during the inspection.

Regarding this issue, the GAC made clear any violation of regulations will be seriously punished, said the statement.

Following a government restructuring in 2018, China's customs force now boasts 100,000 staff throughout the country with responsibilities for traditional customs as well as border health checks, inspection and quarantine for imported and exported animals, plants and their products, imported and exported food safety and commodity inspection.

The GAC oversees 42 customs districts which operate through a total of 678 customs houses nationwide. The administration has a Guangdong office located in Guangzhou for regional coordination.