HONG KONG - Hong Kong riot police patrolling the route of a banned anti-government march arrested dozens of people on Thursday, stopping crowds from gathering as Chief Executive Carrie Lam hailed the city's "return to stability" at China national day celebrations.

Police were seen rounding up more than 50 people downtown and binding their wrists with plexicuffs before putting them on buses. Police said in a Facebook post that they were looking for two men who threw petrol bombs to bloc traffic in another area of the city.

Protesters wanted to march against Beijing's imposition of a sweeping national security law on June 30 and demand the return of 12 Hong Kong people who were arrested at sea by Chinese authorities in August as they tried to reach self-ruled Taiwan.

Police had banned the protest, citing coronavirus-related restrictions on group gatherings and violence at previous marches. Shoppers and passers-by still broke into pro-democracy chants sporadically, but there was no sign of large crowds.

"It's China's national day but this is Hong Kong’s death day," said Jay, a woman dressed in black, the city's protest attire, as she walked past police.

"Hong Kong people are under a lot of pressure but we have to try and keep fighting for freedom."

Officers, in their hundreds, conducted stop-and-search activities and sent away anyone deemed suspicious. Among those ordered to leave were a teenager playing protest songs on a woodwind instrument, a man dressed in black and holding a yellow balloon - colours associated with pro-democracy supporters - and a woman holding a copy of the Apple Daily anti-government tabloid.

Earlier in the day, Lam attended a flag raising ceremony with other senior Hong Kong and mainland officials in an exhibition centre surrounded by police and security barriers.

"Over the past three months, the plain truth is, and it is obvious to see, that stability has been restored to society while national security has been safeguarded, and our people can continue to enjoy their basic rights and freedoms," Lam said.

Late on Wednesday, police said they had arrested five people for inciting participation in illegal assemblies online.

Anti-government protests, which often turned violent in 2019, have been smaller and fewer this year due to coronavirus restrictions on group gatherings and fears of arrest under the new security law.

The law punishes anything China sees as subversion, separatism, terrorism and collusion with foreign forces with up to life in prison.

'NATIONAL MOURNING'

Four members of the League of Social Democrats, led by veteran activist Leung Kwok-hung, known as Long Hair, marched holding a banner reading “There is no national day celebration, only national mourning."

Groups of four are the largest allowed under coronavirus restrictions.

A sore point for democracy supporters has been the capture of 12 Hong Kong people by Chinese authorities, now in detention in the mainland city of Shenzhen, having been arrested for illegal border crossing and organising cross-border crimes.

All were suspected of committing crimes in Hong Kong related to last year's protests.

Stickers demanding their return were plastered on shop windows in the area where police were trying to prevent protests.

China's national day is resented by many democracy supporters who say Beijing is eroding the wide-ranging liberties the former British colony was promised when it returned to Chinese rule in 1997.

For pro-Beijing supporters, it is an opportunity to drum up patriotism in China's most restive city.

At the ceremony, Lam praised China's success in curbing the coronavirus and its economic recovery, calling it "a rare bright spot" which "has shown once again the shift of the global economic focus from the West to the East." REUTERS