Photo/IllutrationProtesters carry U.S. flags as they march during a demonstration against "parallel traders" who buy goods in Hong Kong to resell in mainland China in Sheung Shui, near the Chinese border in Hong Kong, on Jan. 5. (AP Photo)

HONG KONG--Protesters in Hong Kong marched through a border town Sunday to oppose traders from mainland China.

They rallied in Sheung Shui, which lies across the border from the mainland city of Shenzhen. For years, traders have bought goods from the district to sell at a markup in Shenzhen. The practice is called “parallel trading" because it happens in a gray area alongside legal trade.

Locals say it pushes up prices and adds to growing tensions between Hong Kong residents and mainland Chinese.

"The mainland Chinese come here, block the streets with their bags ... rents have gone up and it has made things more expensive for Hong Kongers," said Jasmin, a 19-year old student dressed all in black, who only gave her first name.

"I want the government to know that too many of them are coming over here."

Sunday's protests follow a march in central Hong Kong of at least tens of thousands on New Year's Day and an escalation in clashes with the police over the festive period.

The marchers, including families with children, shouted slogans such as "Liberate Hong Kong, Revolution of our times!" and "Patriots use China-made products, don't parallel trade!"

Police maintained a visible presence, with patrols in riot gear standing by at the town's train station and in several areas along the planned route of the march, which had received a police permit to proceed.

While the demonstration was largely peaceful, police said on its Facebook page it earlier fired tear gas to disperse a group of protesters hurling petrol bombs over the fence of the Sheung Shui police station before the march, damaging one police vehicle.

Many shops in the area were closed.

Some black-clad protesters held up signs that read “SARS,” in apparent reference to a mysterious infectious disease that may have been brought to Hong Kong from the central Chinese city of Wuhan, where at least 44 people have been infected.

The outbreak has revived memories of the 2002-2003 SARS epidemic that began in southern China and killed more than 700 people.

About 100 protesters marched through a Sheung Shui mall last month, demanding that mainland Chinese traders leave the territory.

Hong Kong, a semi-autonomous Chinese city, has seen more than 6 months of anti-government demonstrations.

Anti-government protests in Chinese-ruled Hong Kong escalated in June over a now-withdrawn extradition bill, but have since developed into a broader movement, with demands including universal suffrage and an independent inquiry against alleged police brutality.

The police maintain they acted with restraint.

Many people in Hong Kong are angered by Beijing's tight grip on the city which was promised a high degree of autonomy under this framework when the former British colony returned to Chinese rule in 1997.

Beijing denies interference and blames the West for fomenting the unrest.

The protest movement is supported by 59% of the city's residents polled in a survey conducted for Reuters by the Hong Kong Public Opinion Research Institute.

In a Saturday statement, China's ministry of human resources and social security said the head of its Hong Kong Liaison Office, the most senior mainland political official based in the Chinese-controlled territory, had been replaced.

Wang Zhimin, who had held the post since 2017, had been replaced by Luo Huining, who until November was the top communist party official in the northern province of Shanxi.