The Chinese authorities have detained a prominent activist and legal scholar who issued a blistering attack on president Xi Jinping for mishandling the coronavirus crisis amid a nationwide crackdown on speech freedom.

Xu Zhiyong, a former law lecturer and founder of the social campaign New Citizens Movement, was taken away by police on Saturday evening while he was seeking refuge at the home of a lawyer in the southern city of Guangzhou, activists Ye Du and Hua Ze said.

His host Yang Bin, her husband and son were also taken away for “hiding criminals” but were released after 24 hours, they said. Yang has reportedly posted comments online demanding officials be held responsible for the whistleblower doctor Li Wenliang who died this month.

A staff member who answered the phone at the Shilou township Public Security Bureau in Guangzhou refused to comment.

Xu published an essay early this month, which called on China’s president to resign for his lack of ability to govern China, citing the coronavirus crisis and the mishandling of the Hong Kong pro-democracy protests – a dangerous move that guarantees official anger.

“You didn’t authorise the truth to be released, and the outbreak turned into a national disaster,” Xu wrote.

“Whenever you face looming crisis, you’re clueless,” Xu wrote. “I don’t think you’re an evil man, you’re just not wise … Mr Xi Jinping, please step down.”

Facing criticism over Beijing’s handling of the outbreak, Xi said in a speech reported by state media on Saturday evening that he had given instructions on fighting the disease as early as 7 January. The admission has fuelled questions over why the potential dangers of the virus were not conveyed fully to the public at an earlier date.

Xu’s friends said he had been on the run since December, after the authorities cracked down on a secret meeting attended by more than 20 rights lawyers and activists in the southeastern city of Xiamen in Fujian province. More than 10 participants have been summoned or detained mostly on subversion charges since.

Xu’s detention is likely to end in a lengthy jail term, because he has previously been jailed and the authorities tend to punish repeated offenders harshly.

“We’re very pessimistic, it certainly won’t be a light sentence in view of the current situation,” his friend and fellow activist Hua Ze said.

Xu’s detention came amid a nationwide crackdown on freedom of speech amid the coronavirus crisis. The death of whistleblowing doctor Li Wenliang, who was silenced by police after warning colleagues about the coronavirus, sparked public outrage. Law professor Xu Zhangrun, who also published a public critique of Xi, was placed under house arrest for days and now barred from the internet. At least two citizen journalists are reportedly detained.

Activists say the authorities are using the coronavirus epidemic as an opportunity to intensify their crackdown on dissent.

“Whenever there is a political challenge, they would step up on suppression,” said Dr Teng Biao, Xu’s long term fellow activist.

Xu, started his activism in 2003 when he and fellow PhD graduates, Teng and another friend, urged the national legislature to scrap rules on detaining and repatriating migrants. A champion for social equality and the rule of law as part of his New Citizens Movement, he was jailed in January 2014 for four years after writing an open letter critical of Xi and for staging protests for equal rights for migrant children and official transparency over private assets.