Hong Kong - The mystery over the reported abduction from Hong Kong of a Chinese billionaire deepened on Wednesday after a newspaper advert appeared in his name pledging loyalty to China, in a case that has heightened fears over Beijing's meddling. The whereabouts of financier Xiao Jianhua - one of China's richest men - are unclear after reports in overseas Chinese-language media that he was taken from Hong Kong by mainland security agents last week.The reports suggested Xiao's disappearance was part of China's ongoing anti-corruption campaign, which some critics believe has been used to target President Xi Jinping's political opponents.A front-page advert in Hong Kong newspaper Ming Pao, attributed to Xiao, said on Wednesday he had "always loved the (ruling Communist) party and the country" and would soon meet with media."I personally believe the Chinese government is civilised and has rule of law," the advert read."I have not been kidnapped."Xiao, who said in the statement that he was a Canadian citizen, insisted he was being treated for an illness overseas, repeating a denial he had been abducted that had been published on his company's WeChat account Monday.The founder of Beijing-based Tomorrow Group, Xiao has previously denied allegations that he fled to Hong Kong in 2014 to escape a corruption crackdown by President Xi. #Chinese billionaire #XiaoJianhua abducted from #HongKong hotelhttps://t.co/fAAV23JbNa pic.twitter.com/Pmdaf07iyT— Asian Correspondent (@AsCorrespondent) 1 February 2017 He is reported to have acted as a broker for the Chinese leadership, including for the family of president Xi.It is illegal for mainland agents to operate in the semi-autonomous city, but the disappearance of five Hong Kong booksellers known for publishing salacious titles about Beijing's leadership in 2015 prompted widespread criticism that China had overstepped that line.One of the men, Lee Bo, vanished from Hong Kong, triggering international condemnation and local protests that the city's autonomy and rule of law was under fire.Lee always insisted he had gone over the border voluntarily.'Credible suspicion'"After the Lee Bo fiasco people are very concerned about whether Hong Kong residents or people lawfully staying in Hong Kong will be protected," James To of the Democratic Party told AFP.To said there was a "credible suspicion" that Hong Kong's semi-autonomous "one country, two systems" deal had been breached.The Financial Times reported Xiao had been led away by Chinese public security agents from an apartment at the harbourfront Four Seasons hotel.Other reports in local media said Xiao had been staying at the hotel long-term, protected by female bodyguards. The hotel said there was an "active investigation" on Wednesday, and that they could not comment further.When asked about Xiao's case, Hong Kong police said they had received a request for assistance over a "mainland citizen" on Saturday, but that a family member had later retracted it. They said the person it refered to had crossed a border control point between Hong Kong and China on Friday.The Canadian consulate said it was aware of the reports and that officials were "in contact" with authorities.Xiao added in the Ming Pao statement that he was a permanent resident of Hong Kong, as well as holding a diplomatic passport. "Please everyone, don't worry!" he said.