The drill, which comes in the waning days of high tensions with US President Donald Trump's administration, was conducted in the country's central desert region.
Iran has won US approval to transfer funds for coronavirus vaccines from overseas, the central bank chief said on Thursday, as its daily death toll fell to a three-month low.
The US military said the drill had caused two bases with American troops in the region to go on heightened alert.
"After increasing military threats against Iranian vessels headed for Venezuela, an order was issued to Iran's armed forces to identify and track several US merchant vessels."
Iran’s Foreign Ministry denied that the case was re-opened and said that Levinson's whereabouts were still unknown.
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.