A Chinese-Australian writer who went missing at the weekend has been detained in China, the Australian government says.
Yang Hengjun, a blogger and former Chinese diplomat, has not been heard from since flying from New York to Guangzhou on Saturday.
China has told the Australian embassy that the 53-year-old, a past critic of the Communist Party, is in custody.
The reasons for his detention are not yet clear, Australian officials said.
In a statement, Australia’s Department of Foreign Affairs and Trade said it was trying to “obtain consular access to him… as a matter of priority”.
On Wednesday, a Chinese foreign ministry spokeswoman said that she was “not aware” of the case.
The Australian citizen had been travelling with his wife, Chinese national Yuan Rui Juan, and young stepson.
It is believed that Ms Yuan has been interviewed by Chinese officials in Beijing, after first travelling to Shanghai to leave her son with relatives.
Who is Mr Yang?
He has a sizeable following online and has sometimes written critically about China’s Communist Party, but less so in recent times. He also authors spy novels.
Mr Yang was briefly unreachable on a trip to China in 2011 – prompting fears he was missing – but later attributed the episode to a “misunderstanding”.
He currently lives in New York and is a visiting scholar at Columbia University, said his friend Feng Chongyi, an academic at University of Technology Sydney.
Associate Prof Feng said that he had warned Mr Yang recently against travelling to China, but that Mr Yang had replied that he considered himself to be safe.
Mr Yang had not responded to messages in recent days, his friend said.
“He is one of the most influential bloggers on political issues in China, where he’s earned the nickname of ‘Democracy Peddler’ through talking about democracy and human rights,” Associate Prof Feng told the BBC on Wednesday.
What else has happened recently?
Correspondents say Mr Yang’s case follows a similar pattern to the cases of the two Canadian citizens, Michael Kovrig and Michael Spavor, who were detained in China in recent weeks.
In both cases, the foreign ministry initially said it had no knowledge of them being held, then confirmed they were in the hands of state security a few days later.
Australia has previously expressed “concern” about the arrests of the Canadians.
China has denied the detention of the two men is tied to Canada’s arrest of a senior Huawei official, Meng Wanzhou, but many analysts believe it is a tit-for-tat action.
Mr Yang’s detention comes as Australian Defence Minister Christopher Pyne is due to visit Beijing on Thursday.