Asia-Pacific markets reverse gains as investors assess Trump address on Iran war

Asia-Pacific markets reversed gains on Thursday as investors assess an address by President Donald Trump on the Iran war.

During his speech, Trump reiterated that the U.S. objectives in Iran were almost met and said that "we have all the cards" in the conflict. He also said that Washington will hit Iran "very hard" over the next two to three weeks.

Early Wednesday stateside, Trump claimed that Iran's "New Regime President" had asked the U.S. for a ceasefire, a claim that Tehran has denied.

Trump added that the U.S. will "consider" the offer only once the Strait of Hormuz was "open, free, and clear," he said on Truth Social.

Trump previously said he was willing to end the U.S. military campaign against Iran even if the Strait of Hormuz remained closed, according to a report by the Wall Street Journal.

Japan's Nikkei 225 was down 1.4% after Trump's address, while the Topix fell 0.94%.

South Korea's Kospi dropped 2.82% and the small-cap Kosdaq was down 3%.

Australia's S&P/ASX 200 started the day in positive territory, but was also down 0.48%.

Hong Kong's Hang Seng index opened 0.5% lower shortly after the speech, while the CSI 300 index on mainland China was flat.

U.S. stock futures were little changed, with S&P 500 futures and Nasdaq-100 futures just above the flatline. Dow futures were up 13 points, or 0.03% higher.

Overnight in the U.S., the S&P 500 advanced 0.72%, and the Nasdaq Composite gained 1.16%. The Dow Jones Industrial Average added 0.48%.

—CNBC's Lisa Kailai Han and Sean Conlon contributed to this report.