Five AstraZeneca employees have been detained in China amid allegations of potential illegal activity by the British pharmaceutical giant.

Authorities in Shenzhen, China, are investigating how the company collected patient data, Bloomberg reports, as well as the import of a liver cancer drug that has not yet been approved in China.

An AstraZeneca spokesman said: “We are aware that a small number of our employees in China are under investigation and we have no further information to provide at this stage.”

It threatens to cast a shadow over AstraZeneca’s Chinese operations. The company is the largest foreign pharmaceutical company in China, making 12% of its revenue there. In 2019, it employed 15,000 people in its Chinese operations, out of 90,000 employees worldwide.

Pascal Soriot, the president, praised China for encouraging innovation. He said companies in the country were creating “first-in-class products or new technologies that will shape the future of medicine.”