Iran's Islamic Revolution Guard Corps (IRGC) says it has successfully launched a military satellite into orbit for the first time.
The satellite, named Nur (Light), reached an orbit of 425km (264 miles) after being carried by a three-stage Qased launcher, a statement said.
The success of the launch has not been verified independently.
But US Secretary of State Mike Pompeo said Iran had violated a UN resolution and needed "to be held accountable".
He spoke shortly after President Donald Trump tweeted that he had instructed the US Navy to "shoot down and destroy any and all Iranian gunboats if they harass our ships at sea".
Trump appeared to be referring to an incident in the Gulf a week ago, in which the US said 11 IRGC Navy vessels repeatedly conducted "harassing" approaches of six US Navy and Coast Guard ships .
(Source: BBC News)