US equity indexes traded mixed in midday trading on Wednesday as President Donald Trump's comments downplaying the possibility of an extended war in Iran kept geopolitical risk contained.

The Nasdaq Composite jumped 1.2% to 23,920.8, and the S&P 500 rose 0.5% to 6,999.2. The Dow Jones Industrial Average, however, declined 0.5% to 48,303.5. S&P is trading within hair's breadth of its all-time high of 7,002.28.

Trump said the war with Iran was close to over, telling the world to brace for an "amazing two days," as the army chief of mediator Pakistan arrived in Tehran in a bid to prevent a renewed conflict, Reuters reported. Pakistan's military confirmed Field Marshal Asim Munir had arrived in Tehran, the news report said. A senior Iranian source told Reuters that Munir, who had mediated the last round of talks, was heading to Iran "to narrow gaps" between the two sides.

Meanwhile, Iran's military has threatened shipping in the Red Sea if the US continues its blockade of Iranian ports, after US Central Command said the blockade has "completely halted" Iran's economic sea trade, CNN reported.

West Texas Intermediate crude oil futures rose 1.1% to $92.39, and Brent crude futures climbed 1% to $95.6.

"The bottom line is that despite the market's rally since last week, the current ceasefire remains fragile," Thierry Wizman, global foreign-exchange and rates strategist at Macquarie Group, said in a note. "It is currently not letting the oil flow anyway. And if agreement is not reached on the nuclear issue, hostilities may restart, including in the Red Sea."