Freedom of the press is "not a shield for illegal activities," says the liaison office.
The office said it firmly supports the government and the police force's "just action" in arresting five senior executives of Apple Daily.
"The Basic Law guarantees Hong Kong residents' freedom of speech and freedom of the press," the office said. "But rights and freedoms have boundaries and no one can cross the borderline of national security, which is also expressly stipulated in the international conventions and is the common practice in other countries."
It said Hong Kong is a city under the rule of law and everyone is equal before the law, including media outlets.
"Freedom of the press is not a shield for illegal activities," it said. "All persons who violate the national security law and other related laws will be severely punished, regardless of their professional status, backgrounds or the forces supporting them."
Beijing's Office For Safeguarding National Security in Hong Kong also expressed its support for the actions taken by police.
"According to the national security law, all institutions, organizations and individuals in the SAR shall abide by it and other laws concerning the maintenance of national security in Hong Kong and they cannot engage in any act or activity endangering national security," a spokesman said.
Former chief executive Leung Chun-ying echoed the sentiments, saying on Facebook that Apple Daily is "the shame of Hong Kong" and "the shame of the journalism industry around the world."
Leung added: "Calling on other countries to impose sanctions on their own country is regarded as treason all around the world. Do you know the penalty for treason?
"Hongkongers are enjoying great freedom, but they also have the responsibility to safeguard China's sovereignty, national security and interests to ensure Hong Kong is not a weak spot for foreign forces to target China."
Leung, who is the vice chairman of the Chinese People's Political Consultative Conference, said foreign governments - including Britain and Australia - have also raided news organizations suspected of violations.
"No one is above the law. No one is above national security laws. This applies to the press and is part of the definition of press freedom. Anyone who has any doubt about this universal principle could test it against the US, British or Taiwanese authorities," Leung said.
wallis.wang@singtaonewscorp.com
