A Hong Kong bookseller who said he was blindfolded, interrogated and detained in China led a protest march Saturday defying Beijing as pressure grows for authorities to answer questions over the case.

Lam Wing-kee is one of five booksellers who went missing last year -- all worked for a publisher known for salacious titles about leading Chinese politicians.

The case heightened fears that Beijing was tightening its grip on semi-autonomous Hong Kong, with Lam's explosive revelations earlier this week about how he had been detained in China further fanning many residents' concerns.

Lam told AFP Saturday that he did not feel afraid after breaking bail, refusing to return to the mainland and breaking silence on his detention.

"I don't feel scared because there are so many people here," said Lam, surrounded by more than 1,000 supporters who had gathered in Hong Kong to protest against his detention and to demand answers from the city's authorities over the booksellers' case.

"I'm happy to be back in Hong Kong."

He added that he had been contacted by the city's police but had not yet responded to them. He would give no detail about where he was now living.

Leading the rally, he shouted slogans including "Say no to authority!" and "Hong Kong has a bottom line!"

The protesters, carrying banners saying "Fight until the very end" are marching from the Causeway Bay Bookstore, the business at the centre of the controversy, to China's liaison office.

In a surprise press conference Thursday Lam told how he had been blindfolded and transported north after crossing the border into the mainland to visit his girlfriend in October.

Lam said he was kept in a room, interrogated for months and forced to sign away his right to a lawyer or contact with his family.

He also described how he recited a scripted confession broadcast on Chinese state television, admitting to trading banned books, out of fear.

- 'Come clean' -

Pro-democracy lawmakers are demanding to know what Hong Kong authorities have done to help the booksellers, accusing them of being a puppet of Beijing.

They say China has violated the semi-autonomous system under which the city is ruled.

Protester Simon Chan, 60, said it was time for people to speak up.

"If we don't voice out, then this will just continue and we will be very scared," he told AFP.

Beijing has refused to be drawn on Lam's accusations, saying only that it is entitled to pursue the case as he broke mainland Chinese laws.

Hong Kong authorities have expressed "concern", saying they are attempting to speak to Lam.

Pro-democracy lawmakers are urging the government to admit what it knows about the case.

"I request that the government clearly explain what they have done to help Lam or the other Causeway Bay bookstore workers in these past eight months. If they don't, then they're not our government," said legislator Frederick Fung.

In an editorial Saturday, the South China Morning Post, which has recently been criticised for being too Beijing-friendly, also demanded both sides "come clean".

Lam said he was allowed to return to Hong Kong on Tuesday on condition that he go back over the border Thursday, bringing with him a hard disk listing bookstore customers. He says he did not want to hand over the records and decided to speak out instead.

Lam is one of four booksellers under investigation on the mainland for trading banned books in China.

The fifth, Lee Bo, the only bookseller to disappear on Hong Kong soil, has said he is simply helping with enquiries and is currently back in the city.

He has refuted Lam's claims that Lee told him he had been taken to the mainland against his will.

Hong Kong people 'petrified' over bookseller revelations
Hong Kong (AFP) June 17, 2016 - Hong Kong lawmakers say residents have been left "petrified" by explosive revelations from a city bookseller about his detention in China and have slammed Beijing for violating freedoms.

In a surprise interview Lam Wing-kee broke his silence Thursday over how he had been detained on a visit to China and was interrogated for months with no access to a lawyer or his family. He vowed to break bail, refusing to return to the mainland.

Lam, 61, is one of five booksellers who published salacious titles about leading Chinese politicians and disappeared at the end of last year in a case that drew international condemnation and heightened fears Beijing was tightening its grip on semi-autonomous Hong Kong.

Pro-democracy lawmakers accused Hong Kong authorities of failing to help the booksellers and called on them to ensure Lam is now kept safe after his decision to speak out.

Emily Lau of the Democratic Party said if Lam were harmed it would "shatter" Hong Kong.

"Many Hong Kong people are petrified," she told AFP.

"It can happen to each and every one of us."

The government says it is trying to speak to Lam and that residents' safety is paramount.

China's foreign ministry would not be drawn on the criticisms of its treatment of Lam, saying only that he had violated Chinese law.

"Authorities here have the right to deal with the relevant case in accordance with the law," said spokeswoman Hua Chunying Friday.

One pro-democracy lawmaker said Chinese authorities were acting like "thugs" and accused the Hong Kong government of being a puppet of Beijing.

"Hong Kong is being pathetic," said Claudia Mo of the Civic Party.

"It has to say something to regain people's confidence... but it is terrified to do anything that might embarrass Beijing."

Some residents said they now questioned how safe they are in Hong Kong.

"People feel scared," accountant Louis Chan, 28, told AFP.

"Now the Chinese government want to have full control."

- Protesters gather -

A succession of political groups protested outside China's liaison office in Hong Kong Friday with more demonstrations expected Saturday.

High-profile teenage activist Joshua Wong called Lam a hero.

"Lam is the role model for Hong Kong people -- facing the suppression of the communist regime," Wong said.

Lam was kept in detention for eight months and returned to Hong Kong Tuesday. He was due to go back over the border Thursday but decided to speak out instead.

Lam told how he recited a scripted confession about involvement in the illegal book trade on state television in fear of what would happen to him.

In harrowing detail he also explained how the toothbrush he was given in detention was tied by a thread which was held by a guard to prevent him from committing suicide by swallowing it.

Fellow booksellers Lui Por and Cheung Chi-ping returned to Hong Kong in March on bail, but both were reported to have quickly gone back to the mainland.

Their colleague Lee Bo, who says he went to China of his own free will and is helping mainland authorities with their inquiries, has also been back and forth to Hong Kong.

Lee's case caused the most outcry because he was the only bookseller who disappeared on Hong Kong soil, prompting allegations that Chinese enforcement agents were operating illegally in the city.

The fifth man, Swedish citizen Gui Minhai, remains in detention.

The Swedish embassy in Beijing said Friday that repeated requests for a meeting with Gui had not been granted since they last saw him in February.