Security chief Lai Tung-kwok has cast doubt on the ability of Occupy Central organisers to prevent their civil disobedience movement from turning violent, saying "radicals" are almost certain to hijack it once it starts.
The storming of the Legislative Council foyer by activists on Friday, Lai writes in an article published in newspapers today, "clearly shows how a peaceful demonstration can lose control, resulting in the emergence of violent crisis".
Even Friday's protest in Legco against new town development in the northeast New Territories illustrated this, he said. "Most remained calm and exercised restraint in the face of radicals' call to barge in and occupy the [Legco] chamber."
Occupy Central organisers vow to bring the city's commercial hub to a standstill if the government fails to come up with a plan that meets the hallmarks of genuine democracy for the 2017 chief executive election.
In his article of almost 2,000 words, Lai also reiterates that "robust action" will be taken against any attempt to challenge the city's law and order, and that no cause, including civil disobedience, is above the law.
"As the objectives, visions, strategies and means of expression of the protesters of public processions differ, the radicals will take the opportunity to hijack the movement and turn peaceful public meetings into violence, deviating from the original plan of the organisers," he writes.
"Once violent confrontation occurs, the situation may become irrevocable and things could get out of control."
Chan said Occupy participants would not be easily provoked, as those who had signed its letter of intent would already have gone through a long deliberation process before they blocked the streets of Central.
In the conclusion to his article, Lai writes: "We will ensure that the law enforcement agency will act in accordance with the law and will take robust action to uphold the rule of law and to maintain public safety and public order."