China’s blue-chip CSI300 Index dropped 1.3% by the lunch break, while the Shanghai Composite Index lost 1%. Hong Kong benchmark Hang Seng was down 1.6%.

The CSI300 index has shed 1.2% so far this week, on track for its biggest weekly loss since late-July, while the Hang Seng Index has lost 3%, set to extend losses from the previous week, if the current trend persists.

“Investor sentiment has largely shifted as the market turns volatile, with most in wait-and-see mode amid political ups and downs,” UBS analysts said in a client note.

“There’s more downside risk and higher uncertainty than a week ago. Until the year-end, clients will continue to like sectors such as technology, basic materials, and new consumer,” they said.

Tech majors listed in Hong Kong have fallen nearly 7% this week, set for their worst week since April 7.

Trade tensions between the world’s two largest economies escalated this week, as the US and China began charging additional port fees on ocean shipping firms that move everything from holiday toys to crude oil.

Chinese sanctions imposed this week on US affiliates of shipbuilder Hanwha Ocean to undermine South Korea-US cooperation and “to coerce” Washington’s Asian ally, a US state department spokesman said on Friday.

Semiconductor shares traded onshore fell 2.8%, while the tech-focused STAR50 index dropped 2.6%.

The elite Central Committee of China’s ruling Communist Party will hold a closed-door meeting from Monday to Thursday to discuss, among other things, the country’s 15th five-year development plan.