Hong Kong shares ended at a five-week low on Wednesday, in line with a global sell-off as traders grow concerned about a possible US-led military strike on Syria.
The benchmark Hang Seng Index fell 1.60 percent, or 350.12 points, to 21,524.65 on turnover of HK$63.10 billion ($8.14 billion).
Oil giant PetroChina fell 4.4 percent to HK$8.27, its lowest since late June. Shares of the company's natural-gas unit Kunlun Energy fared even worse, shedding 14 percent to HK$10.88.
Trading in shares of both companies was halted on Tuesday, ahead of PetroChina's disclosure after the market closed that three of its senior executives had resigned and were under investigation by China for "severe disciplinary violations".
While the investigation will hurt shares in the short term, operations at both companies are unlikely to be affected, analysts said.
Chinese shares closed down 0.11 percent. The benchmark Shanghai Composite Index slipped 2.27 points to 2,101.30 on turnover of 132.2 billion yuan ($21.5 billion).
"The index took a negative lead from regional markets," Zheshang Securities analyst Zhang Yanbing told AFP.
But he added losses were capped by optimism over approval of a free-trade zone for Shanghai.
State media said Tuesday that China's national legislature was reviewing plans for the zone, which was formally approved by the central government last week.
Shanghai International Port Group rose by its 10 percent daily limit to 3.74 yuan, while Shanghai Material Trading also surged 10 percent to 11.99 yuan.
Medical shares were among the biggest losers, with Kangmei Pharmaceutical off 10 percent at 19.33 yuan and Merro Pharmaceutical down 5.43 percent at 6.45 yuan.
PetroChina closed down 0.50 percent at 7.95 yuan.
-- Dow Jones Newswires contributed to this report --