Regional markets retreated as oil prices jumped more than 2 percent following a report by Iran's state television that seven oil tankers caught fire and were damaged in the Strait of Hormuz. In Hong Kong, the benchmark Hang Seng Index dived 717 points, or 3.03 percent, to 22,934 on turnover of HK$256.05 billion. The tech index plunged 200 points, or 5 percent, to 3,793 while the Chia enterprises index fell 254 points, or 3.2 percent, to 7,689. Dickie Wong, executive director of research at uSmart Securities, said he wasn't bullish in sentiment for the rest of the quarter, given that local stocks fell to a nearly four-month low. "We are now testing new lows, and probably may test a year-low again – 22,500 points. It may have some kind of rebound, but I don't really see much upside amid concerns about the increasing tension between China and US, and weakening of the Hong Kong dollar," he said. "Market sentiment is totally changed, especially AI-related and the tech sector facing regulatory pressure. Those negative factors contributed to this market sell-off." Up north, the benchmark Shanghai Composite Index ended down 55 points, or 1.48 percent, at 3,658. The Shenzhen Component Index dived 347 points, or 2.97 percent, to 11,357 while the ChiNext Index plunged 117 points, or 4.37 percent, to 2,576. Turnover on the main Shanghai and Shenzhen indices amounted to around 1.53 trillion yuan, up from 1.44 trillion yuan on Wednesday. If the Iran report is verified, it would be the largest number of vessels damaged in the waterway in a single day since the Iran war started on February 28 in the wake of attacks by US and Israeli forces. Brent crude, the international standard, gained 3.2 percent to US$112.27 per barrel. It has been bouncing between US$97 and US$112 in recent days on uncertainty about when the war with Iran will allow the global energy industry to return to normal. US benchmark crude rose 2.8 percent to US$99.80 per barrel. AI stocks, at the centre of market action in recent months, are under pressure from worries that construction of data centres may slow as it is becoming increasingly expensive to borrow money. In Tokyo, the Nikkei share average tumbled 1,713 points, or 2.65 percent, to end at 62,907 on heavy selling of big tech companies like SoftBank Group, which lost 6.9 percent. The broader Topix slipped 46 points, or 1.14 percent, to 3,997. In Seoul, the Kospi closed down 201 points, or 3.52 percent, at 5,533 amid chip-sector profit-taking and the central Bank of Korea's hawkish policy stance on further interest rate hikes. (Additional reporting by agencies) Edited by Edmond Fong