The two journalists had sheltered in Australian diplomatic offices for several days before being allowed to leave China
The two journalists had sheltered in Australian diplomatic offices for several days before being allowed to leave China AFP / FRED DUFOUR

Three and a half weeks after journalist Cheng Lei was detained by Chinese authorities without a clear reason, Beijing has finally revealed the Australian citizen is being held on “national security grounds.”

An English news presenter for China Global Television Network (CGTN), Cheng has been in Chinese detainment since August 14. At the time, there was no reason given as to why she was being held up, but Australian authorities confirmed that she was in the communist government’s custody.

In a briefing Tuesday, China’s foreign ministry spokesperson Zhao Lijian has revealed the reason behind its government’s decision to detain Cheng. Zhao said Beijing has taken “compulsory measures” against Cheng on suspicion of “criminal activity endangering China’s national security.”

It is still unclear what “criminal activity” she may have allegedly committed.

China's announcement came just a day after the last two journalists working for Australian media in China flew back to Sydney, BBC reported. ABC’s Bill Birtles and AFR’s Mike Smith landed in the state on Tuesday.

Birtles told BBC that Chinese police also told him he was involved in a “national security investigation” and was not allowed to leave the country. He contacted the Australian consulate and stayed at the embassy for four days

Before leaving, he was interviewed by the police about Cheng and his sources on Hong Kong’s national security law.

“I know her, but not particularly well, it didn't seem like I would be the most logical person to interrogate if you wanted evidence about her case," the journalist said.

Smith confirmed that he too was questioned about Cheng.

The events follow months of growing strain on the relationship of Canberra and Beijing. Both nations used to rely heavily on each other for trade, but have since thrown back-and-forth blows at each other.

Australia in April asked for a global investigation into the origins of COVID-19 which is believed to have come from Wuhan, China. In response, China imposed restrictions on beef and barley exports. It has also issued a travel warning against Australia and accused the country of espionage.