China's immigration authorities have seized a total of 4.07 tonnes of drugs in 186 drug-related cases at border ports and in border areas so far this year, according to data released on Friday.

A total of 243 suspects have been apprehended in the operations, the National Immigration Administration said.

In recent years, China's immigration authorities have implemented a holistic approach to national security and adhered to a strict anti-drug policy.

A spokesperson for the National Immigration Administration said immigration authorities will continue to improve the multi-layered border security and drug control system, enhance anti-drug investigation techniques and tactics and strengthen cross-border law enforcement cooperation.

June 26 is the International Day Against Drug Abuse and Illicit Trafficking.