Hong Kong police said Monday they had made nine arrests after discovering "suspected" explosives, with media reports linking the find to this week's legislative vote on a controversial political reform package.
"The Organised Crime and Triad Bureau has conducted an operation and discovered a certain amount of suspected explosives in Sai Kung," a spokesman told AFP.
Police confirmed nine people had been arrested in connection with the explosives, but gave no details.
Media reports said the explosives had been found at an abandoned television studio in the east-coast district of Sai Kung in the New Territories.
The South China Morning Post and the Oriental Daily 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.
The Post said police suspect the explosives "were intended to be detonated before the Legislative Council debates on the government's political reform package this week".
The reform bill lays out a plan for choosing the city's next leader by public vote for the first time in 2017.
But it sticks to a ruling from Beijing which stipulates that candidates must be vetted by a loyalist committee.
That ruling sparked mass rallies and roadblocks towards the end of last year, with campaigners dismissing it as "fake democracy".
Lawmakers will vote on the bill by the end of this week, with pro-democracy legislators vowing to block it. There will be nightly rallies ahead of the vote.
Hong Kong is semi-autonomous after being handed back to China by Britain in 1997 and sees much greater freedoms than on the mainland, but there are fears that those are being eroded.
"Localist" groups are frustrated with the lack of progress on electoral reform and have argued that Hong Kong should distance itself from Beijing to forge its own political future.
Officials from two localist groups told AFP they had no knowledge of the arrests and did not condone violence.
"Police said localist activists are making bombs, but I am not sure if it's real or not. We have nothing to do with that," said Jon Ho of Hong Kong Localism Power.
People Power's Tam Tak-chi added: "People Power did not do that. Our group does not believe in violence."