China’s powerful state spy agency and six other government departments have taken the unusual step of stationing investigators in the offices of Didi Chuxing to conduct a security probe of the ride-hailing group.

The review, which sent Didi’s share price plunging when it was first announced after the company’s $4.4bn US initial public offering earlier this month, marks the first time the secretive Ministry of State Security has publicly announced it will temporarily base staff inside a company.

The Cyberspace Administration of China, the regulator in charge of co-ordinating the cyber security review on Didi, said on Friday the probe would also involve the police, tax authorities, the market competition regulator, as well as industry regulators for natural resources and transport.