President Trump has warned the US is “targeting” 52 Iranian sites and will strike “very fast and very hard” if Tehran attacks Americans or US assets.
The president’s remarks followed the US assassination of Qasem Soleimani, a top Iranian general, in a drone strike.
Soleimani’s killing was a major escalation between the two nations, and Iran vowed to take “severe revenge”.
Writing on Twitter, Mr Trump accused Iran of “talking very boldly about targeting certain USA assets”.
He said the US had identified 52 Iranian sites, some “at a very high level & important to Iran & the Iranian culture”, and warned they would be “HIT VERY FAST AND HARD” if Tehran struck at the US.
The president said the targets represented 52 Americans who were held hostage in Iran for more than a year from late 1979 after they were taken from the US embassy in Tehran.