The Hong Kong police will be clearing the main Occupy site at Admiralty on Thursday and are making it clear that a whole range of options - including tear gas - are "possible" in trying to disperse protesters.
The police will start by cordoning off swathes of the business district in Admiralty and parts of the financial hub in the adjacent Central.
Anyone found within the area will either be "dispersed" or be arrested if they refuse to leave after an ultimatum is issued, said a senior police source briefing the media on Wednesday night.
This is even as the Hong Kong Federation of Students and Scholarism called for people who had previously joined in the protest to return and stay together until the police clear the site.
Student leader Alex Chow said that staying put means that they refuse to give in to the government and that they will consider "non-violent ways" of confronting the police.
When asked if tear gas will be used to disperse protesters refusing to leave, the police source made it clear that "all options are possible".
"It depends on the behaviour of the protesters. We are prepared for trouble, like what happened last Sunday," he said, in reference to protesters' attempt to surround the government complex and occupy a new road, leading to violent clashes with the police.
He said that the decision will be based on what is "absolutely necessary".
Operations on Thursday will take place in two phases: first, starting at 9am, court bailiffs will take the lead in executing an injunction for parts of Harcourt Road to be cleared, with officers moving in on both ends - from Central in the west and from Wan Chai in the east.
This can take up to two hours. The police may step in to assist the bailiffs if resistance is encountered.
Then, the police will take over to clear those sections not covered by the court order.
The objective is to reopen all roads to traffic.
Officers will be on standby to ensure that protesters will not try to reoccupy the roads.
They will also take action to arrest those who are engaging in "unlawful" behaviour outside the cordoned off area.
This is to pre-empt what had happened in Mong Kok two weeks ago when the protest site was cleared. Protesters displaced from the cleared road then congregated at another street instead.
On whether the final protest site in Causeway Bay will be demolished on Thursday as well, the police source said that it is possible but will depend on progress made in Admiralty.
Since the Occupy movement began on Sept 28, a total of 655 people have been arrested. Some have been charged, some are on bail while others are still being investigated.
A total of 129 police officers have been injured.