The Hang Seng Index fell 2.2 per cent to 25,705.68 as of 10.05am local time, matching a six-day run in early January. The Hang Seng Tech Index dropped 2.5 per cent.
On the mainland, the CSI 300 Index slid 1.7 per cent and the Shanghai Composite Index retreated 1.4 per cent.
Biotech major WuXi AppTec, which has a huge exposure to the US, tumbled 6.3 per cent to HK$105.30 and its affiliate WuXi Biologics slumped 5.6 per cent to HK$35.76. Alibaba Group Holding sank 3.7 per cent to HK$159.30 and Tencent Holdings shed 2.5 per cent to HK$635.
The markets reacted to US President Donald Trump’s threat on Friday to impose a 100 per cent tariff on all Chinese imports and restrict exports of critical software from November 1. The threat was a response to Beijing’s move to tighten exports of rare earths and their processing technology. These metals are used to make defence equipment and green-energy products.
However, Trump has indicated that he is willing to engage in talks with China to resolve the dispute. Trump and his Chinese counterpart Xi Jinping are scheduled to meet at the Apec summit in South Korea later this month.