President Donald Trump said on Friday that he halted retaliatory strikes on Iran over the downing of a US surveillance drone to prevent high casualties.
"We were cocked & loaded to retaliate last night on 3 different sights when I asked, how many will die. 150 people, sir, was the answer from a General. 10 minutes before the strike I stopped it, not proportionate to shooting down an unmanned drone," Mr Trump said on Twitter, confirming earlier reports that US forces had been preparing to launch attacks when they were called off.
"I am in no hurry, our Military is rebuilt, new, and ready to go, by far the best in the world," the US president said. "Sanctions are biting & more added last night. Iran can NEVER have Nuclear Weapons, not against the USA, and not against the WORLD!"
He did not specify what the sanctions were, and there was no announcement of any fresh punitive action from the Treasury Department.
Mr Trump did not say which sites were to be attacked but senior administration officials quoted by the New York Times said Mr Trump had approved stries against targets such as radar stations and missile batteries.
US House of Representatives' Speaker Nancy Pelosi voiced her relief on Friday that Trump had decided not to strike Iran.
"A strike of that amount of collateral damage would be very provocative, and I'm glad the president did not take that," Pelosi said.
She urged Trump to seek congressional approval before any military action against Iran.
A day after tensions escalated in a chain of fast moving events, Trump told American news channel NBC on Friday that he is not looking to go to war with Iran.
"I'm not looking for war, and if there is it'll be obliteration like you've never seen before. But I'm not looking to do that."
According to Iranian officials who spoke to Reuters, the US president also sent a message to Tehran through Oman to warn that a US attack on Iran was imminent but he would rather begin talks.
"Trump said he was against any war with Iran and wanted to talk to Tehran about various issues ... He gave a short period of time to get our response but Iran's immediate response was that it is up to Supreme Leader [Ayatollah Ali] Khamenei to decide about this issue," one of the officials said.
"We made it clear that the leader is against any talks, but the message will be conveyed to him to make a decision," a second official said. "However, we told the Omani official that any attack against Iran will have regional and international consequences."
The US has requested a closed-door UN Security Council meeting on Iran and the latest developments in the Gulf, a senior diplomat told The National on Friday.
The discussions will take place in private and are planned for Monday afternoon, focusing on the recent attacks against oil tankers in the Gulf and the Iranian downing of the US spy drone, the diplomat said.
The downing of the Global Hawk drone in the Strait of Hormuz, which the Pentagon says was above international waters but Iran says was over its territory, raised tensions between the US and Iran even further after a series of attacks on tanker ships in the region that Washington blamed on Tehran.
On Friday Iranian state television broadcast images purporting to be of debris from the drone, which it claimed was recovered inside its territorial waters.
The US barred until further notice all American civilian flights from the area where the drone was shot down. The Federal Aviation Administration order cited danger to flights "demonstrated by the Iranian surface-to-air missile shoot-down of a US unmanned aircraft system".
Mr Trump had struck a combative tone in his initial response to the attack. "Iran made a very big mistake!" he said on Twitter on Thursday. "This country will not stand for it, that I can tell you," he said later at the White House, where he held meetings with top officials and Congressional leaders to discuss the attack.
As fears rose of open conflict between the US and Iran, something both sides have said they do not want, Mr Trump softened his comments.
"I find it hard to believe it was intentional, if you want to know the truth," he said. "I think that it could have been somebody who was loose and stupid that did it."
The president's mixed message left the world unsure what Washington's next move would be.
"You will find out," Mr Trump said when asked about possible retaliation.
Senior Republicans called for a "measured response" to the incident after their meeting with Mr Trump, saying the president and his national security team "remain clear-eyed on the situation and what must be done in response to increased Iranian aggression".
The Democratic House Speaker Nancy Pelosi called for de-escalation. The "dangerous, high-tension situation" needed a "strong, smart and strategic, not reckless, approach", she said.
The main point of dispute is whether the drone was in violation of Iranian airspace and therefore a legitimate target.
Iranian Foreign Minister Mohammad Javad Zarif said that parts of the drone had been recovered in Iranian territorial waters, as Tehran moved to bring the incident before the United Nations.
"We don't seek war, but will zealously defend our skies, land and waters," Mr Zarif said.
The Pentagon denounced the "unprovoked attack", claiming the navy drone was 34 kilometres from Iran when it was destroyed by a surface-to-air missile.
But Iran's Islamic Revolutionary Guard Corps said it brought the drone down as it was "violating Iranian air space" over the waters of Hormozgan province.
Mr Zarif provided coordinates to back the claim.
"At 00:14 US drone took off from UAE in stealth mode & violated Iranian airspace," Zarif tweeted. "It was targeted at 04:05 at the coordinates (25°59'43"N 57°02'25"E) near Kouh-e Mobarak."
"We've retrieved sections of the US military drone in OUR territorial waters where it was shot down," he wrote on Twitter.
In a letter to the UN Security Council and UN Secretary General Antonio Guterres, Iran protested against a "dangerous and provocative act by the US military forces against the territorial integrity of the Islamic Republic of Iran".
But the Pentagon published a map showing the flight path of the drone, which indicated it travelled outside of Iranian waters and included a photograph showing it was at the coordinates (25°57'42"N 56°50'22"E) when it was downed.
The drone downing came as Iran was already accused by Washington of carrying out attacks on tanker ships in the congested Hormuz area. Tehran denies involvement but has frequently threatened to block the sea lanes used to ship much of the world's oil exports.
The commander of the US Naval Forces Central Command, Sean Kido, said a mine allegedly used in one of the attacks matched Iranian weaponry and that incriminating fingerprints had also been collected.
The shipping attacks came soon after the US decision to beef up its military presence in the region in response to counter Iranian threats and as Iran faces increasing pressure on its economy as a result of US sanctions that have greatly curbed it own oil exports.
The sanctions were re-imposed last year after Mr Trump pulled the US out a deal to curb Iran's nuclear programme. He has repeatedly said he does not favour war with Iran unless it is to stop the country getting a nuclear weapon, something Iranian leaders insist they are not pursuing.
But Trump critics say his policy of "maximum pressure" – crippling economic sanctions, abandonment of the nuclear agreement, and sending forces to the region – make war ever more likely.
A key Republican ally, Senator Lindsey Graham, said the president's "options are running out".
Asked if he believed the countries were nearing conflict, he replied: "I think anybody would believe that we're one step closer."
"They shot down an American asset well within international waters trying to assess the situation. What are you supposed to do?"