Whatsapp and Facebook are "pausing" all such reviews "pending further assessment of the impact of the National Security Law, including formal human rights due diligence and consultations with human rights experts," a WhatsApp spokeswoman told the WSJ.

In the week since President Xi signed the law into effect, protesters who took to HK's streets in defiance are already being arrested and prosecuted under the law, which makes carrying pro-democracy or pro-independence 'signage', including the Hong Kong independence flag, a fixture at Hong Kong's pro-democracy protests last year.

While politicians, including many Republicans, have spoken out, American companies have been mostly silent on Hong Kong, probably fearing retaliation from the Chinese elite, who control access to the lucrative Chinese market. Facebook is the first social media company to implement such a brazen policy.