The move shows that international governments are losing faith in the city's human rights protections, politicians say.
Chinese tourists take photos of the exhibit marking the 30th anniversary of the massacre, but are reluctant to have a conversation on the topic in public.
Thirteen villagers and a local reporter now face possible jail terms.
Dissidents Jia Huajiang and Liu Xuehong are being held in immigration detention, and fear repatriation to China.
