Candidates in Hong Kong's September elections must by law pledge that the city is an "inalienable" part of China, and advocating independence could end their candidacy, the head of the Electoral Affairs Commission (EAC) said on Tuesday.

The comments come after the EAC and the Hong Kong government sparked anger by saying candidates for the legislative council, which includes activists for democracy and independence, are required to declare in a new confirmation form that the city falls directly under the central government in Beijing.

The Hong Kong government also said that advocating and promoting independence is "contrary" to that declaration and could render a candidate ineligible. The EAC said anyone making a false declaration is "liable to criminal sanction."