While in Hong Kong, Chen uploaded several video diaries and observations about the protests to the Twitter-like Weibo, where his account has more than 770,000 followers. The diaries have since been deleted from his Weibo account but are still available on YouTube.

Chen indicated to the South China Morning Post on Wednesday evening that he was safe, then explained in audio messages on Thursday morning that he had returned to Beijing.

“No one sent me or invited me to Hong Kong. I went purely out of my curiosity about what was happening there,” Chen said.

“In my broadcast online, I only reported objectively what I saw and what I learned in the city.”

Chen said he hoped the political crisis in Hong Kong could be resolved peacefully. “I hope everyone could sit down for a rational conversation while keeping their love for a country and a city in mind,” he said. “I hope I can visit Hong Kong again and enjoy the city as a traveller.”

In his last video filmed at Hong Kong International Airport on Tuesday night, Chen said he was forced to cut his trip short and return to the mainland because of pressure from mainland police and lawyers associations. He said he could be disqualified from practising law because of his visit.

“I’m showing everyone my lawyer’s licence here. Why? Because it may not be mine any more after I return,” he said.

“I studied for three years for this ‘toy’ … If you asked me whether destroying three years of hard work in three days was worth it, I would say of course not. But there is nothing that I can do; I am who I am … I alone bear the consequences of my actions.”

Chen confirmed in a WeChat post on Wednesday that he had returned to mainland China. “I wish to see Hong Kong again without wearing a mask,” he said in a comment on his WeChat post from the same day that was later deleted.

Human rights watchers and activists have expressed concerns over what might befall Chen in the long term after his return to the mainland.

“Although Chen did not publicly support the Hong Kong protesters, in the past there have been cases of mainlanders harassed or taken away by the authorities after attending protests in Hong Kong,” said Doriane Lau, a China researcher at Amnesty International Hong Kong.

“It is surely rare to see a [mainland] human rights lawyer attending public protests in Hong Kong, especially when the crackdown on human rights lawyers in China has been increasingly harsh.”

While in the city, Chen said he did not take state media reports at face value and came to see what was happening for himself.

Beijing’s state-run media has aggressively criticised the protesters in recent weeks, warning that further chaos and violence would destroy Hong Kong.

Xu Zhihan, a human-rights activist on the mainland, posted a message on Weibo on Wednesday saying Chen had arrived back but he had not been able to get in touch with him.

Chen became widely known on the mainland after winning second place in a nationwide televised public speaking competition in 2014. He regularly posts social commentary videos on his Weibo account.

Attempts to contact Xu on Wednesday were unsuccessful.

Wang Yaqiu of Human Rights Watch said she “wouldn’t be surprised” if Chen was punished for observing the protests, which have plunged Hong Kong into its biggest political crisis since the 1997 handover over a now-abandoned extradition bill.

“The Chinese authorities have for a long time used disqualification to silence human rights lawyers. Particularly after the ‘709’ crackdown in 2015, authorities have systematically used the suspension of licensees to muzzle human rights lawyers,” Wang said.

She said other mainlanders had joined the Hong Kong protests but had maintained a low profile.

Additional reporting by Su Xinqi