Journalists' unions in Hong Kong say they are troubled by the dismissal of a veteran editor of a newspaper that published a report on the Panama Papers document leak revealing offshore business dealings of the rich and powerful.

A statement of concern from the Ming Pao Staff Association followed the dismissal of Keung Kwok-yuen, the paper's No. 2 editor, at midnight Wednesday, purportedly to save operating costs.

Eight other Hong Kong journalist associations said in a joint statement that they were shocked by Keung's dismissal and that Ming Pao's management owed its readers and the public an explanation.

Some Hong Kong journalists and politicians are worried about the growing influence of Beijing on the semiautonomous Chinese territory, which retained its own civil liberties when handed over from Britain in 1997.