Sweden has condemned China’s “brutal” detention of Swedish citizen Gui Minhai, escalating a stand-off sparked two weeks ago when Chinese agents seized the Hong Kong-based bookseller as he travelled with Swedish diplomats.

Foreign minister Margot Wallstrom questioned the rule of law in China and characterised Mr Gui’s detention on January 20 on a Chinese train as “contrary to basic international rules on consular support”. She demanded that China disclose Mr Gui’s whereabouts and detail his alleged crime.

Ms Wallstrom said: “The brutal intervention in January against a Swedish support measure was implemented despite repeated Chinese assurances that Gui Minhai was a free man at the time.”

Hours later, Chinese foreign ministry spokesman Geng Shuang hit back at Sweden for “irresponsible” comments and told reporters at a regular briefing that Mr Gui was being held lawfully under “coercive measures”, without giving details. The term is a euphemism for detention.

Ms Wallstrom’s statement marks a tougher stance from Sweden two weeks after 10 Chinese security agents seized Mr Gui as he travelled to Beijing accompanied by two consular officials to seek medical treatment. Stockholm’s initial silence over the incident drew criticism from activists and the media in Sweden and beyond.

Mr Gui, 53, sold gossipy books about Chinese leaders in Hong Kong before he disappeared for the first time in 2015, when he was believed to have been abducted by Chinese agents from his seaside home in Thailand. At the time, speculation in publishing circles contended that Mr Gui was on the verge of releasing a new book about a former mistress of the Chinese president, explaining concerted efforts by Beijing to silence him.

He was released into house arrest in October in the eastern city of Ningbo after Chinese authorities said he turned himself in over a hit-and-run accident which allegedly occurred years before.

Western officials said they had been assured by China that Mr Gui had been freed, but agents believed to be from China’s state security apparatus, possibly fearing that Mr Gui would leave the country, seized him a second time in January.

Mr Geng would not respond to Sweden’s demand that Mr Gui’s alleged crimes be disclosed, and instead chastised Stockholm for going public with its criticism.

The Chinese spokesman said: “The Swedish side should know well about the seriousness of the case, as well as the disgraceful roles that certain Swedish people played in the case.

“China will by no means accept the irresponsible remarks made by the Swedish side repeatedly in defiance of our notice.”

Germany’s ambassador to China, Michael Clauss, backed Ms Wallstrom’s statement, saying “there is no doubt that Sweden has the support of all of us as members of the EU”.

US state department spokeswoman Heather Nauert and European Union ambassador Hans Dietmar Schweisgut have also called on China to immediately release Mr Gui.

Mr Gui was one of five Hong Kong booksellers whose disappearances symbolised China’s determination to enforce a hard line on political dissent and a free press, despite international criticism.

AP