Australian journalist Cheng Lei returned home on Wednesday after being detained by Chinese authorities for more than three years on national security charges.

Here are some other high-profile cases of foreign nationals detained in China:

The Australian writer has been detained in China for more than three years, and in 2021 was tried in Beijing on undisclosed national security charges. His arrest coincided with worsening relations between Australia and China and a verdict in his case has been repeatedly delayed.

Yang, who was born in China but is an Australian citizen, has denied working as a spy for Australia or the United States.

Friends of the pro-democracy blogger say they fear for his deteriorating health in detention.

A Japanese employee of Astellas Pharma Inc, who has not been identified publicly, was detained in Beijing in March on suspicion of espionage, sending a chill through the Japanese business community in China.

The man in his 50s worked in China for more than 20 years and is an executive, according to Japanese media reports. Beijing was expected to decide soon on whether to formally arrest the businessman, Kyodo reported last month.

The Chinese foreign ministry, when asked last month if the Japanese employee had been arrested, said foreign nationals in China must abide by the country's laws or be prosecuted otherwise.