Hong Kong police said Monday they had arrested nine members of a "local syndicate" involved in making explosives and said at least one claimed to be a member of a radical group.

Hong Kong police said Monday they had arrested nine members of a "local syndicate" involved in making explosives and said at least one claimed to be a member of a radical group.

Police would not name the group or specify motives but said that maps of central districts of Hong Kong had been found and warned anyone taking part in public gatherings to stay away from "violent protesters".

It comes as a series of rallies are planned ahead of a vote this week on a controversial political reform package which has divided the city and led to mass protests at the end of last year.

"The operation... resulted in the arrest of nine Hong Kong citizens for the offence of conspiracy to manufacture explosives," Au Chin-chau, superintendent of the organized crime and triad bureau, told reporters.

"During police inquiries someone claimed to be a member of a local radical organization," said Au.

Au would not clarify how many of the group belonged to the organization, but said "not all".

He described the group as a "local syndicate involved in manufacturing explosives".

The South China Morning Post and the Oriental Daily had earlier said those arrested were activists from pro-democracy "localist" groups, which have emerged in the wake of a battle over the government's electoral roadmap.

Five men and four women were arrested aged 21 to 34 years old.

Chemicals were seized at an abandoned television studio in the eastern district of Sai Kung, with some detonated at the scene.

A house search later led to the seizure of ingredients which could be used to make TATP, "a form of high explosive", said Au.

Maps of the central neighborhoods of Wan Chai and Admiralty were also found.

Both locations were at the heart of last year's mass pro-democracy rallies and the government complex is in Admiralty.