After a few minutes of trading, the Dow Jones industrial average is up 0.5 percent, while the broad S&P 500 index is up 0.2 percent and the technology-heavy Nasdaq composite index is up 0.1 percent.
On Wednesday afternoon, Trump threatened Tehran with new, harsh attacks and also announced that the United States would "in the not too distant future" take over the island of Kharg in the Strait of Hormuz, which is important for oil production, as well as other oil infrastructure.
There are no major effects yet on oil prices as a result of the move; at 3:30 p.m., a barrel of North Sea oil was trading at just over $92.
