Police in Hong Kong have searched the office of a think tank after its former executive was put on a wanted list last month. The move is apparently aimed at strengthening the clampdown on anti-government activities.

The police announced on Monday that they inspected the office of the Hong Kong Public Opinion Research Institute and questioned its head, Chung Ting-yiu.

They said their search was carried out in connection with a former executive who has been accused of inciting secession through social media posts. The man left Hong Kong for Britain three years ago.

The think tank, led by university researchers, has conducted opinion polls asking Hong Kong citizens about top government officials, the freedoms of speech and the press, and humanitarian issues, such as the Tiananmen Square incident.

Authorities have been stepping up pressure on survey activities critical of the government since the national security law took effect in 2020.