A pro-democracy campaigner who fled Hong Kong has been denied entry to Singapore despite being granted a visa, as the city-state declared his presence would not be in its national interests.

Nathan Law, who currently lives in exile in the UK, arrived in the country on Saturday to attend a closed-door, invitation-only conference. However, he was detained at the border for several hours before being deported.

I was not asked questions and they did not give reason for the denial, he told the BBC.

Law, formerly a local legislator in Hong Kong, is one of eight activists currently wanted by Hong Kong authorities, facing accusations of endangering national security.

Singapore has an existing extradition treaty with Hong Kong, heightening concerns around geopolitical influence in the region. According to the Ministry of Home Affairs, his entry into Singapore presented a threat to national interests, which led to further checks upon arrival.

Law speculated that the denial of his entry was politically motivated, questioning whether external influences from the People’s Republic of China were involved, directly or indirectly.

He mentioned that he had applied for a visa well in advance, which was approved three weeks before his departure, and he holds a UK Refugee Travel Document. Following his deportation, Law was placed on the earliest flight back to San Francisco.

The event organizers where he was supposed to speak have declined to comment, while Hong Kong’s government has urged him to return and surrender to authorities.

This incident is not isolated; Singapore has previously enacted measures against Hong Kong activists, maintaining a firm stance against foreign political involvement in its domestic affairs.