Meng, 64, the first Chinese head of the international law enforcement agency headquartered in France, was "taken away" for questioning by discipline authorities "as soon as he landed in China" last week, Hong Kong-based South China Morning Post quoted a source as saying.

It was not immediately clear why he is being investigated or exactly where he is being held.

Meng, who is also a vice-minister at China's Ministry of Public Security, is under investigation in China, the Post reported amid mystery surrounding his disappearance after his wife reported to the French police that he had gone missing.

The French police said on Friday that they have launched a probe for Meng after being contacted by his wife.

Interpol, which is based in Lyon, said on Friday that it was aware of reports of Meng's "alleged disappearance” and that the issue was a matter for the relevant authorities in France and China.

Meng was last seen in France on September 29, according to reports from France.

So far neither the public security ministry nor the foreign ministry in China has commented.

Under China's supervision law, a suspect's family and employer must be notified within 24 hours of detention, except in cases where doing so would hinder an investigation. It appears Meng's wife was not informed.

Reports quoted an unnamed French judicial official as saying that Meng arrived in China at the end of September but there had been no news of him since.

While Meng is listed on the website of China's Ministry of Public Security as a vice-minister, he lost his seat on its Communist Party Committee -- its real decision-making body -- in April, the Post reported.

According to his own page on the site, Meng's last official engagement was on August 23, when he met Lai Chung Han, a second permanent secretary of Singapore, it said.

Meng was appointed the head of Interpol in 2016. His appointment also sparked concern about China extending its crackdown on dissidents abroad. He is due to serve until 2020.

Interpol is the world's largest agency facilitating police cooperation with 192 member countries.