Oil prices fell even as U.S. officials warned that renewed military action against Iran could come after the Nov. 3 midterm elections.

In a big week for central bank news, markets are awaiting the outcome of a meeting of the European Central Bank later Thursday. The Bank of Japan is expected to stand pat when it wraps up its policymaking meeting on Friday.

Tokyo's Nikkei 225 climbed 1.1% to 64,659.47. OpenAI investor SoftBank Group's shares gained 1.8%.

In South Korea, the Kospi lost 1.2% to 5,937.66.

Samsung Electronics, a key component of the Korean market, sank 4.1% despite announcing strong quarterly results as its latest shareholder return policy arrangements disappointed some investors. Memory chipmaker SK Hynix rose 2.6%. Its shares soared 10.9% the day before on the company's better-than-expected quarterly results.

The Taiex in Taiwan, which has also benefited from the AI boom, declined 1.4%.

Hong Kong's Hang Seng shed 0.6% to 22,958.65. The Shanghai Composite index declined 0.8% to 3,651.43.

Australia's S&P/ASX 200 gained 0.5% to 8,891.80.