China to impose retaliatory sanctions over US law on Hong Kong

"Hong Kong will now be treated the same as mainland China," he added.

The executive order calls for blocking the US property of any person determined to be responsible for or complicit in "actions or policies that undermine democratic processes or institutions in Hong Kong," according to the text of the document released by the White House.

It also directs officials to "revoke licence exceptions for exports to Hong Kong," and includes revoking special treatment for Hong Kong passport holders.

Critics of the security law fear it will crush the wide-ranging freedoms promised to Hong Kong when it returned to Chinese rule in 1997, while supporters say it will bring stability to the city after a year of sometimes violent anti-government protests.