A university student from mainland China and two 14-year-olds are among eight suspects charged over a rally at a Hong Kong shopping centre, where protesters demonstrated on Saturday against so-called parallel traders and shoppers from across the border.

Fanling Court heard on Tuesday that Guangdong Polytechnic Normal University student He Zhenyu, 20, had caused a commotion along with four local teenagers – including a 14-year-old boy – by shouting at customers at a Mannings pharmacy in the Landmark North shopping centre in Sheung Shui.

After customers left and the pharmacy closed, the five students dropped screws and advertising posters on the shop floor through gaps in the folding gate at the entrance, senior prosecutor Alan Yau Sik-lun said.

He, together with Sin Ka-hei, 18, Cheng Tsz-shun, 18, Jerry Chan Yu-kwan, 16, and the 14-year-old, were charged with one joint count of disorderly conduct in a public place.

Two others, unemployed Cheng Ka-leung, 24, and cook Fung Man-tat, 27, faced another joint count of assaulting a police officer, after they allegedly attacked two officers who rushed to the scene to arrest offenders.

The prosecution only identified the officers as X and Y.

Yau said officer X was punched in the left eye and face while officer Y was slapped in the head.

A 14-year-old girl was charged with possession of offensive weapons, after officers intercepted her in the vicinity and found she had a 30cm hammer.

The eight defendants were not required to enter a plea, as acting Principal Magistrate Don So Man-lung adjourned the case until April 14 pending further police inquiries.

Yau said the force would examine the screws and posters seized at the scene and inspect security camera footage.

So released all the defendants on HK$5,000 (US$641) cash bail, but imposed a travel ban and curfew on them. He also ordered them to report to police twice a week, and banned them from setting foot in the Landmark North mall.

He, the mainland student, had a seven-day permit to visit Hong Kong and the magistrate told him to apply to the Immigration Department for an extension because of the case.

So dismissed the defence’s application for an exception to the curfew requirement on New Year’s Eve.

The eight defendants were among 20 people arrested during the protest on Saturday. Ten men and a woman were released on police bail and must report back again in February.

Chan Chun-hin, 16, who was accused of robbing an officer’s gun in the rally, was charged with three counts at Fanling Court on Monday. His bail application was declined.