The Dow Jones industrial average had fallen 0.6 percent shortly after opening, the broad S&P 500 index 0.4 percent and the technology-heavy Nasdaq composite index 0.5 percent.
Earlier on Tuesday afternoon, US President Donald Trump threatened Iran in a post on Truth Social that "An entire civilization will die tonight," but also wrote that something revolutionary and "wonderful could happen."
The price of WTI oil has risen after the president's post and is trading at around $116 per barrel at 3:30 p.m.
