Four men and six women, aged 26 to 43, were arrested on suspicion of conspiring with the "612 Humanitarian Relief Fund" to take donations from organisations abroad to help groups that support people in exile or promote sanctions against Hong Kong, police said in a statement.

Hong Kong authorities have been taking concerted action against pro-democracy dissent since Beijing imposed a national security law on the former British colony in 2020 after months of at times violent anti-government protests rocked the city the previous year.

The relief fund was set up in 2019 to help pay legal and medical costs of arrested protesters.

Police did not identify the 10 but said their homes and offices were being searched and documents and electronic devices had been seized.

The suspects were under investigation and further arrests were not being ruled out, police said.

The 2020 national security law punishes various acts including subversion and collusion with foreign forces with up to life in prison.

Six people including five former trustees of the fund were arrested in May on suspicion of colluding with foreign forces. The arrested former trustees included a former Catholic bishop, Cardinal Joseph Zen, former legislators Margaret Ng Ngoi-yee and Cyd Ho Sau-lan, pop singer Denise Ho Wan-see, and cultural studies scholar Hui Po-keung.

They were released on bail and later found guilty of a lesser offence of failing to register the fund and fined HK$4,000 ($512).

Governments including the United States and Britain have criticised the national security law as a tool of repression.

Chinese and Hong Kong officials say it has restored stability in the financial hub.

(Reporting by Jessie Pang; editing by Greg Torode, Robert Birsel)

By Jessie Pang