US President Donald Trump approved but then scrapped strikes against Iranian targets on Thursday (June 20th), after Iran shot down a US drone in what the president termed a "big mistake".
The US was planning to hit "a handful of Iranian targets, like radar and missile batteries" Thursday evening, the New York Times reported, citing senior administration officials, but the plan was suddenly aborted in its early stages.
Iran said earlier it had recovered parts of a US Global Hawk spy drone in its territorial waters after downing the aircraft in a missile strike, but the Pentagon says it was above international waters when it was hit.
On Friday, Trump announced that he called off planned strikes on Iran because the expected death toll of 150 people would not have been a "proportionate" response to Tehran shooting down an American drone.
The downing of the drone near the strategic Strait of Hormuz has seen tensions between the two countries spike further after a series of attacks on tankers the US has blamed on Tehran.
Iran vowed Friday to defend its borders after downing the drone, with the commander of the aerospace arm of its Islamic Revolutionary Guard Corps (IRGC) saying the aircraft was warned twice before it was fired on over the Gulf of Oman, without specifying the means of warning.
Iran's deputy foreign minister Abbas Araghchi provided Swiss ambassador Markus Leitner, whose country represents US interests in Iran, with "indisputable" evidence the drone had violated Iranian airspace, the foreign ministry said.
The US special representative on Iran, Brian Hook, said Tehran was "responsible for escalating tensions in the region" and accused it of rejecting diplomatic overtures to deescalate the situation.
"Iran needs to meet diplomacy with diplomacy, not military force," Hook told reporters in Saudi Arabia.
The US Federal Aviation Administration warned of danger to flights "demonstrated by the Iranian surface-to-air missile shoot-down of a US unmanned aircraft system", and barred American civilian aircraft from the area "until further notice".
Major non-US airlines including British Airways, KLM, Lufthansa and Qantas said they too were altering flight paths to avoid the sensitive Strait of Hormuz area.
The Pentagon says the Global Hawk drone -- one of the most expensive pieces of equipment in the US arsenal, costing over $120 million apiece -- was 34 kilometres from Iran when destroyed by a surface-to-air missile in an "unprovoked attack".
It published a map showing the flight path of the drone, which indicated it travelled outside of Iranian waters and included a photograph showing its coordinates when it was downed.
Zarif provided different coordinates for the downing of the drone by a domestically-manufactured Khordad 3 air defense battery.
The shootdown came as Iran was already accused by Washington of carrying out attacks on tankers in the congested shipping lanes heading out of the Gulf through the Strait of Hormuz.
Tehran denies any involvement.
Trump has repeatedly said he does not favor war with Iran unless it is to stop the country getting a nuclear weapon.