China in 2020 enacted a sweeping national security law in Hong Kong after the finance hub saw months of huge and sometimes violent protests calling for greater democratic rights.
Authorities have arrested more than 260 people under the law, with around 80 of them convicted or awaiting sentencing.
Police said the two men arrested Tuesday, aged 33 and 59, were suspected of “conspiracy to collusion with a foreign country or with external elements to endanger national security”.
They were also accused of “conspiracy to incite others to commit riot”, police added.
The two men, who authorities did not name, were linked to the “612 Humanitarian Relief Fund”, a now-defunct group that helped pay legal and medical costs for people arrested during the 2019 protests.
The duo were suspected of colluding with the fund to “receive donations from various overseas organisations to support people who have fled overseas or organisations which called for sanctions against Hong Kong”, police said.
Identical allegations were made on August 10 when Hong Kong police arrested 10 other people with ties to the fund.
The fund disbanded in October 2021 after national security police demanded it hand over details that included information about its donors and beneficiaries.
Authorities have accused the group of fomenting dissent among jailed protesters and scrutinised its ties with Hong Kong activists who have fled overseas.
Last month, police put out bounties of HK$1 million ($128,000) each on eight pro-democracy activists living abroad, accusing them of violating the security law.
Some of the targeted activists have decried the bounties as “harassment” and the move was condemned by the United States, Britain and Australia.