HONG KONG--In implementing the national security law for Hong Kong, police will have sweeping authority that allows them to take actions including conducting searches without a warrant, restricting suspects from leaving the city, and intercepting communications.

Hong Kong's government issued the details of Article 43 in the city's national security law on Monday night, which outlines the measures that the police force can take to implement the legislation in the city.

According to the rules, police may be authorized to conduct searches for evidence without a warrant in “exceptional circumstances.” Police may also apply for a warrant that requires a person suspected of violating the national security law to surrender their travel documents, thus restricting them from leaving Hong Kong.

Additionally, under the rules, written notices or restraining orders may be issued to freeze or confiscate property if there are “reasonable grounds” to suspect that the property is related to an offense endangering national security.

Platforms and publishers, as well as internet service providers, may also be ordered to take down electronic messages published that are “likely to constitute an offence endangering national security or is likely to cause the occurrence of an offence endangering national security.”

Service providers who do not comply with such requests could face fines of up to 100,000 Hong Kong dollars ($12,903) and receive jail terms of six months.

Individuals who post such messages may also be asked to remove the message, or face similar fines and a jail term of one year.

Before the release of the implementation rules on Monday, Facebook, WhatsApp and Telegram said that they would deny law enforcement requests for user data in Hong Kong as they assess the effect of the national security law.

The companies did not immediately respond to requests for comment on the new implementation rules.

Under the implementation rules, Hong Kong chief executive Carrie Lam may also authorize police to intercept communications and conduct surveillance to “prevent and detect offences endangering national security."

Finally, written notices may also be served to a foreign political organisation or Taiwan political organisation, or individual agents, to furnish details on their activities related to Hong Kong. This includes details such as personal particulars, assets, income, and expenditure of the organization in Hong Kong. Failure to comply or providing false or incomplete information can result in a fine of 100,000 Hong Kong dollars ($12,903) or imprisonment of six months or two years respectively.

The details of the implementation rules come into effect Tuesday and details were released after the Committee for Safeguarding National Security of the Hong Kong Special Administrative Region, chaired by Lam, convened its first meeting on Monday.

Hong Kong's national security law, imposed last week following anti-government protests in Hong Kong last year, makes secessionist, subversive, and terrorist activities illegal, as well as foreign intervention in the city’s internal affairs. Any activities such as shouting slogans or holding up banners and flags calling for the city’s independence are a violation of the law regardless of whether violence is used. The maximum penalty is life imprisonment.

Critics see it as Beijing’s boldest step yet to erase the legal firewall between the former British colony and the mainland’s authoritarian Communist Party system.

Hanscom Smith, U.S. consul general to Hong Kong and Macau, said Monday that it is a “tragedy” to use the semi-autonomous Chinese territory’s new national security law to chip away at freedoms in the Asian financial hub.

“Using the national security law to erode fundamental freedoms and to create an atmosphere of coercion and self-censorship is a tragedy for Hong Kong,” Smith told reporters. “Hong Kong has been successful precisely because of its openness and we’ll do everything we can to maintain that."

Since the law went into effect, the government has specified that the popular protest slogan “Liberate Hong Kong, revolution of our time” has separatist connotations and is thus criminalized.

In Hong Kong’s public libraries, books by pro-democracy figures have been pulled from the shelves, including those written by prominent pro-democracy activist Joshua Wong and politician Tanya Chan. The authority that runs the libraries said it is reviewing the books in light of the new legislation.

Many pro-democracy shops that publicly stood in solidarity with protesters have removed pro-democracy notes and artwork that adorned the walls of their stores, fearful that they might violate the new law.

A 23-year-old man, Tong Ying-kit, was the first person in Hong Kong to be charged under the new law, for allegedly driving a motorcycle into a group of policemen while bearing a flag with the “Liberate Hong Kong, revolution of our time” slogan.

Tong appeared in court Monday facing charges of incitement to secession and terrorist activities. He was denied bail.

Separately, pro-democracy activists Agnes Chow, Joshua Wong and Ivan Lam also appeared in court Monday over charges related to a protest last June. Chow pleaded guilty to inciting others to participate in an unlawful assembly, as well as to participating in an unauthorized assembly.

Wong, who was indicted on similar charges, pleaded not guilty. Lam, who was charged with inciting others to participate in an unlawful assembly, also pleaded not guilty. All three were released on bail.

“With the risk of our personal safety, with the threat of life sentencing, we might be worried, and also being targeted by Beijing, but we also encourage the global community to let our voice be heard in the world,” Wong told reporters Monday. "We still hope to let the world know that now is the time to stand with Hong Kong, and now is the time for Hong Kongers to keep our momentum.”

The cases will move to trial and sentencing following a pretrial review for Wong and Lam scheduled for Aug. 5.

A group of about 10 protesters gathered at a shopping mall in Hong Kong’s Central business district on Monday holding up signs calling for city leader Carrie Lam to step down, as well as reiterating protesters’ demands from the pro-democracy movement last year. The demands include an independent inquiry into the police and greater democracy.

Others held up blank pieces of paper as a sign of protest against the suppression of political protest in the city. About 20 riot police later entered the mall, detaining protesters holding up signs, although they did not appear to make any arrests.

“We feel worried that we may be convicted for expressing our views,” said protester Anthea Wong. “That’s why we are using white paper instead.”