Missing Hong Kong bookseller Lee Bo appeared on television Monday insisting he had not been abducted by mainland authorities, in a case that has sparked a backlash over Chinese interference in the city.

British citizen Lee is one of five Hong Kong booksellers known for publishing titles critical of Beijing who have gone missing in recent months.

It was the first time Lee, 65, had spoken publicly since he was last seen at a Hong Kong book warehouse in December -- Britain said earlier this month it believed he had been "involuntarily removed to the mainland".

In his interview with Hong Kong-based Phoenix television, Lee stuck to a story he had previously given in letters sent back to his family that he had gone to the mainland of his own accord.

He said he had now given up his British passport.

"Many have sensationalised my British citizenship and have complicated the situation, so I have decided to give up my British citizenship," a smiling Lee said in the interview.

Britain had said his disappearance was a "serious breach" of an agreement signed with Beijing before the city was handed back to China in 1997 which protects its freedoms for 50 years.

That earned the ire of Beijing, which blasted Britain for interfering in its domestic affairs.

In the television interview, Lee said he had "resorted to illegal immigration" to get to the mainland as he did not want to draw attention to his visit.

"The reason I went to the mainland was to cooperate in a judicial investigation," he said.

Previous letters purportedly sent by Lee had said he was "assisting" Chinese authorities, but were widely questioned by politicians, residents and rights groups.

- TV confessions -

The other four booksellers, who are under criminal investigation on the mainland, also appeared on Phoenix Sunday admitting to smuggling illicit books into China in sombre, sometimes tearful interviews.

Such confessions are more usually paraded on state television -- Phoenix is a private channel which broadcasts both in Hong Kong and in mainland China.

The case has heightened fears of increasing interference by Beijing in semi-autonomous Hong Kong and sparked international protests.

The men all worked for the Mighty Current publishing house in Hong Kong, which produced salacious titles about political intrigue and love affairs at the highest levels of Chinese politics.

Lee's disappearance triggered the greatest outrage as he was the only one to have disappeared from Hong Kong -- the others went missing in October and were last seen in Thailand or southern China.

The European Parliament has called for the immediate release of all five men.

Earlier Monday, Hong Kong police said Bo had met with them and immigration officials at a guesthouse on the mainland.

Lee told them he returned to China "by his own means voluntarily" and was not abducted, but refused to give further details, police said in a statement.

He said he did not need help from the Hong Kong government but asked police not to disclose where he was staying.

Police said they would continue to follow up on the case and were seeking more information from mainland police about the four other men.

One of the other booksellers, Gui Minhai, a Swedish citizen, confessed he had "explored ways to circumvent official inspections in China", in his television interview Sunday.

In their first appearance since they were detained, fellow booksellers Cheung Chi-ping, Lui Por and Lam Wing-kee blamed the company's illegal book trade on Gui in their interviews.