More than 1000 protesters have marched in downtown Hong Kong to demand the release of Chinese artist Ai Weiwei.
The high-profile artist was detained on 3 April as he was about to board a flight to Hong Kong.
The BBC says his whereabouts remain unknown.
He is a vocal critic of the Beijing government, complaining about a lack of basic freedoms and often incorporating these political themes into his work.
The Chinese government says he is under investigation for suspected economic crimes and has warned the international community, which widely condemned his detention, not to interfere.
