International rights group Amnesty International said on Monday it would close its Hong Kong offices because a China-imposed security law had now made it “effectively impossible” for rights groups to work freely without the risk of reprisals.

Anjhula Mya Singh Bais, the chair of Amnesty’s international board, said in a statement that the two offices would close by year-end, noting an intensification of a crackdown that has forced at least 35 groups to disband under the law this year.

“This decision, made with a heavy heart, has been driven by Hong Kong’s national security law, which has made it effectively impossible for human rights organisations in Hong Kong to work freely and without fear of serious reprisals,” said Singh Bais.

“The environment of repression and perpetual uncertainty created by the national security law makes it impossible to know what activities might lead to criminal sanctions,” she added.

A Hong Kong Security Bureau spokesman said in response to a Reuters request for comment that “every person or organisation must abide by the laws of Hong Kong”, and that the security legislation“upholds human rights”.

In the past, Hong Kong had served as one of Asia’s leading NGO hubs, with groups drawn to its robust rule of law and wide-ranging autonomy.

Among the groups to have disbanded this year are several leading trade unions, NGOs and professional groups, while a number of other NGOs including the New School for Democracy have relocated to the democratic island of Taiwan.