Police arrest independence activist Andy Chan and seven others as the city braces for more protests this weekend.

The founder of a banned Hong Kong independence party has been arrested in a raid where weapons and explosives were allegedly found, a senior police source said, as the city reels from weeks of anti-government protests.

In a statement, police said on Friday that eight people – seven men and one woman – were arrested at an industrial building on Thursday evening in the district of Sha Tin, on charges of possession of an offensive weapon and possession of explosives without a licence.

The arrest comes as more demonstrations are expected across the city this weekend.

The statement did not identify the individuals arrested. But a senior police source told AFP news agency that independence activist Andy Chan was among those detained.

“Andy Chan was arrested inside a premise with (a) gasoline bomb seized,” the source said, asking not to be identified.

Chan’s independence party, the Hong Kong National Party, was outlawed last year on the grounds it posed a national security threat, the first such ban since 1997.

His party had only a few dozen members but its formation infuriated Beijing, which sees calls for independence as an absolute red line.

The banning of his party and the expulsion of a Financial Times journalist, who chaired a talk with Chan at the city’s press club before the party was outlawed, were held up as two examples of sliding freedoms in Hong Kong as Beijing clamps down on dissent.

The South China Morning Post reported that a crowd of protesters gathered outside Sha Tin police station overnight, shouting slogans and throwing eggs at the building.

Semi-autonomous Hong Kong has endured two months of protests that began with a government bid to introduce a law that would have allowed extraditions to mainland China.

The demonstrations evolved into a movement for deeper democratic reforms and an end to eroding freedoms, in the most significant challenge to Beijing’s rule since the city’s handover from Britain in 1997.

On Friday night, thousands of Hong Kong civil servants are expected to hit the streets in support of protesters and to urge authorities to rebuild confidence in the government as escalating protests rock the Asian financial hub.

An open letter by a group of civil servants asked Hong Kong leader Carrie Lam to agree to five public demands: withdraw the extradition bill completely; stop calling the protests ‘rioting’; waive all charges against those arrested; set up an independent commission of inquiry; and restart political reform.

Medical workers also plan to demonstrate late on Friday, with large-scale protests planned for the weekend in Mong Kok, Tseung Kwan O and Western districts.