HONG KONG • Missing Hong Kong bookseller Lee Bo may have asked the police to drop his case and even met his wife in China over the weekend, but the Hong Kong government will still pursue his disappearance, said the city's leader.

In his first remarks on the case since Mr Lee Bo's reunion with his wife Sophie Choi last Saturday, Hong Kong Chief Executive Leung Chun Ying was quoted by the South China Morning Post (SCMP) as saying that the city's police, as part of a follow-up in the case, had written another letter to the Guangdong Provincial Public Security Department, asking to meet Mr Lee.

"There have been cases - of different natures - in which we requested assistance from mainland authorities, and the time we waited for a reply was even longer than for Lee's case," the SCMP quoted MrLeung as saying ahead of a weekly executive council meeting yesterday.

However, he was vague about what steps his government would take if it did not get a response from the Guangdong authorities.

Legislative Council president Jasper Tsang was quoted as saying on Monday that Hong Kong's government should appeal to Beijing for an answer if none was forthcoming after a certain amount of time had passed. "We don't want to see it drag, I think the SAR government understands that," he was quoted as saying by the SCMP, referring to Hong Kong as a special administrative region.

Mr Lee, 65, was "healthy and in good spirits" across the border, and was " assisting an investigation as a witness", according to a Hong Kong police statement on Sunday.

Hong Kong's Sing Tao newspaper published a photo on Sunday of Mr Lee and his wife, as well as a letter said to have been written by him, in which he said he is "free and safe".

Mr Lee is a partner of Hong Kong publishing firm Mighty Current, which specialises in political titles about China's leaders. Four of his associates have also gone missing since last October.

There was no immigration record of Mr Lee, a British citizen, having left Hong Kong when he disappeared on Dec 30 last year, Agence France-Presse reported.

Guangdong Public Security Department deputy director Li Qing-xiong could not explain how Mr Lee managed to enter the Chinese mainland without a home return permit, the SCMP reported.

The surprise reunion of Mr Lee with his wife, at a guesthouse in a secret location in mainland China, has also triggered more controversy, the SCMP reported.

The Hong Kong government allegedly had no clue about the meeting until Ms Choi told the police about it hours later, sparking accusations that the authorities on the mainland were shutting it out, it said.