Chinese mainland-linked stores, banks and bookshops in Hong Kong were again singled out for attack on Sunday as rioters tore through central Kowloon.

In the 20th straight weekend of social unrest in the city, household names, including snacks giant Best Mart 360, Xiaomi Hong Kong, Bank of China, Chung Hwa Book Company and Chinese medicine company Beijing Tong Ren Tang, were bashed in the rampage.

The flagship store of Xiaomi — a mainland electronics company — in Mong Kok was seriously damaged as rioters ripped off posters and pulled down boards in front of the store and pried the shutters open. In the evening, rioters set fire to the front portion of the store, with thick black smoke engulfing the premises before firefighters arrived.

It was the second time the shop had come under attack this month.

Mobs also pried open the shutter at Bank of China’s Jordan branch and smashed counters. Bank of China’s ATMs on the streets were burned. At a Chung Hwa Book Company bookstore, its doors were smashed, bookshelves were overturned and books scattered on the floor.

A branch of Bank of East Asia in Mong Kok was mistakenly vandalized. Its glass windows and doors were smashed, but rioters painted graffiti with the word “sorry” on its walls. Bank of East Asia is a Hong Kong-based banking and financial services company.

Besides mainland-linked enterprises, some political parties were also targeted. The office of a district councilor of the Democratic Alliance for the Betterment and Progress of Hong Kong — the city’s largest political party — was seriously damaged as rioters stormed it, overturned file cabinets and left documents scattered on the ground.

Lau Siu-kai, vice-president of the Chinese Association of Hong Kong and Macao Studies — the nation’s leading Hong Kong affairs think tank — said the specific targets singled out by the rioters showed that they’re discontented with the central government instead of just opposing the now-withdrawn extradition bill.

He said as protesters are unable to attack the Liaison Office of the Central People’s Government in the HKSAR again as they did on July 21, they have to pick mainland-linked businesses as targets, adding it’s also a challenge to the central government’s jurisdiction over the special administrative region.

Lau said such vandalism will widen the rift between the pro-establishment and opposition camps, and have a deterrent impact on voters in next month’s district council elections. Under such circumstances, he said it would be difficult to ensure fair elections.

He said the HKSAR government is now under greater pressure to upgrade its physical force and use tougher legal means to curb the violence and illegal acts.

The Hong Kong Federation of Trade Unions voiced “severe condemnation” of the rioters’ illegal acts, calling them “heinous”. It said such violence and vandalism not only affect residents’ normal life, but also greatly threaten public safety.

The federation urged residents to draw a clear line with rioters and denounce the violence.