The incident is one of the most serious in recent months targeting an areas where US forces are present in Iraq.
Following the re-imposition of US sanctions, a senior Iranian maritime official said Iran had adopted new tactics and new destinations in shipping its oil exports.
US pulls staff from Erbil consulate and European countries end training of Kurdish Peshmerga
If the Iran war talk sounds familiar, it might be because there are elements that resemble the lead-up to the 2003 Iraq War, not least among them the Israel factor.
War between the US and Iran is probably not in the cards, even as the US ups pressure on Iran via sanctions and a military build-up in the region.
The US has concentrated naval power and B-52s in the Persian Gulf in recent days.
The Secretary of State's comments come after the recent US military build-up in the Middle East.
The Trump administration sees Iran’s behavior as another instance of why it pulled the U.S. out of the deal in the first place: the Iranian regime is not trustworthy.
Iran has dismissed the new US deployments, including of an aircraft carrier, as old news announced now to intimidate it through "psychological warfare."
The sanctions target two people and three firms that Washington accuses of being involved in schemes to help the armed Shi'ite group backed by Iran evade American sanctions.