French police investigating the disappearance of Interpol chief Meng Hongwei have placed his wife under protection after threats, the interior ministry said.

Mr Meng's wife contacted police in Lyon, the French city where the international police agency is based, after not hearing from him since 25 September, and after receiving threats by phone and on social media, the ministry said.

A person familiar with the investigation into the disappearance said the initial working assumption of Western investigators was that Meng had antagonised Chinese authorities in some way and had been detained as a result.

"France is puzzled about the situation of Interpol’s president and concerned about the threats made to his wife," the ministry said.

Mr Meng's wife, who has remained in Lyon with their children according to police sources, was receiving protection, it said."Exchanges with Chinese authorities continue," the ministry added.

China has not commented officially on Mr Meng's disappearance and there was no mention of him in official media today.

There have been several cases in recent years of senior Chinese officials vanishing without explanation, only for the government to announce weeks or even months later that they have been put under investigation, often for suspected corruption.

It was not clear why Mr Meng, 64, who was named Interpol's president two years ago, had travelled to China.

Hong Kong's South China Morning Post quoted an unnamed source as saying Mr Meng had been taken for questioning as soon as he landed in China, but it also was not clear why.

French police are investigating what is officially termed in France a "worrying disappearance".

Interpol, which groups 192 countries and which is usually focused on finding people who are missing or wanted, said it was aware of reports about Mr Meng's "alleged disappearance".

"This is a matter for the relevant authorities in both France and China," the agency said in a statement.