The Hang Seng Index sank 1.6 per cent to 25,357.16 as of 9.47am local time. The Hang Seng Tech Index lost 0.2 per cent. On the mainland, the CSI 300 Index and the Shanghai Composite Index both retreated 0.8 per cent.
Brent oil jumped 1.3 per cent to US$82.46 a barrel and the futures contract for Nymex crude trading in New York added 1.1 per cent to US$75.36 a barrel.
With no immediate sign of an end to the US-Iran war, investors have started to factor in the consequences of a prolonged conflict in the Middle East by trimming their exposure to risk assets. Higher oil prices will weigh on stocks and other risk assets as they would fan inflation and force the US Federal Reserve to delay interest-rate cuts.
Other key markets in the region fell. Japan’s Nikkei 225 slid 3.4 per cent, South Korea’s Kospi tumbled 5.7 per cent and Australia’s S&P/ASX 200 sank 2 per cent.