Hong Kong’s best-known pro-democracy activist Joshua Wong says he has been arrested for allegedly taking part in an illegal meeting. A post on his Twitter account Thursday read: “Joshua is arrested when reporting to Central Police Station at about 1pm. The arrest is related to participating in an unauthorised assembly on Oct. 5 last year.” Wong also said he was told he had “violated the draconian anti-mask law as well,” which prohibited protesters from covering their faces. Hong Kong police confirmed to the South China Morning Post that a 23-year-old man had been arrested for “taking part in an unauthorized assembly.” Wong has been one of the faces of the Hong Kong democracy protests since the Umbrella Movement of 2014, and has been a key figure in winning U.S. Congress support for Hong Kong’s democracy movement.