Hong Kong's new national security law has descended upon the offices of Apple Daily newspaper in a raid that followed the arrest on Monday of billionaire media mogul Jimmy Lai Chee-Ying, the news outfit's founder, along with a top executive.

Based on a Post report, around seven people have been collared in the raid that also included two sons of the newspaper's founder. The clampdown was expected to apprehend more personalities during the police operations, insiders disclosed.

More than a hundred police officers stormed into the Tseung Kwan O offices of Apple Daily. Video footage showed the newspaper's personnel being lined up for identity inspections while other officers scoured through every part of the office.

Armed with a court warrant, the raiding team entered the building Monday morning to dig into crimes that Hong Kong authorities claim imperils the security of the city, as shown on a post by the police on their Facebook page.

The police explained to the company staff what the search warrant was for and asked for their full cooperation as they conducted the sweeping operation.

News personnel was ordered to stop their live broadcast as soon as the police entered the office and filtered through every desk. Journalists were prevented from entering the building's executive offices before police shut down key areas of the newsroom.

Live footage from Apple Daily's YouTube channel showed Lai on handcuff while inside the newsroom with officers of the Hong Kong police surrounding him. Lai is facing charges of conniving with foreign countries.

The 71-year old Lai becomes the most prominent figure to be charged by Hong Kong authorities under its new security legislation which Beijing has implemented to curb defiance on Chinese laws.

Sources bared that Hong Kong's opposition groups may not be included during Monday's raid. During the arrest, police accused one of Lai's sons of conspiring with "foreign and external forces" that threatens national security. The other, who was placed in detention, was suspected of conspiracy to commit fraud, sources disclosed.

Meanwhile, the Democratic Party denounced the raid, saying it is against freedom of expression. It was an "outrageous, shameful attack on press freedom," the director of the Journalism Department of the University of Hong Kong, said as quoted by Tom Grundy in his HKFP report.