that US military assets in the Middle East, including the missile cruiser USS Leyte Gulf, have been put on a 72-hour standby.’
The source said that US troops were woken up at around 2am local time “within the hour” of the proposed strike – but then nothing happened, according to the report.
CALLED OFF STRIKES Among the targets which US military chiefs were targeting was the S-125 Neva/Pechora surface-to-air missile system, the Pentagon official said.
Washington believes the Soviet-era weapon was used to down the drone on Thursday although Iran claims they used the domestically-made 3rd Khordad transporter erector launcher to destroy the aircraft.
The White House and the Pentagon declined to comment officially on the reports.
Earlier, Trump declared that "Iran made a very big mistake" by shooting down the unmanned £102m US spy drone over the Strait of Hormuz.
He also suggested that the downing of the aircraft was a foolish error rather than an intentional escalation of tensions - which have led to rising fears of open military conflict.
Trump said at the White House: "I find it hard to believe it was intentional, if you want to know the truth.
"I think that it could have been somebody who was loose and stupid that did it."
But Iran portrayed the shooting as a deliberate defence of its territory - insisting the drone was flying over their airspace.
FEVERISH TENSIONS However, the Islamic Republic has been accused of using a fake photo in an attempt to 'prove' the aircraft was over its territory.
State-run IRNA news agency shared an image of a damaged drone falling to Earth to illustrate its report.
But it has subsequently emerged that the same image - albeit in a wider crop - was previously used on a report of another drone being shot down over Yemen two year's ago.
Yet, Iran's foreign ministry says it has "undeniable evidence" that the spy plane "was in Iranian airspace".
Iran's deputy foreign minister Abbas Araghji told the Swiss ambassador in Tehran that "some of its wreckage (the flying plane) has been found in Iran's territorial waters," reports Saudi outlet Al Arabiya.
UK Minister flies to Tehran for showdown with Iran FOREIGN Office minister Andrew Murrison is set to fly to Tehran for "urgent
It comes amid mounting international concerns about Iran's behaviour in recent months/
The Foreign Office said the short visit on June 23 comes at a time of "increased regional tensions".
The trip was announced after Donald Trump said the US was "cocked and loaded" to retaliate against Iran for downing an American drone, but cancelled the strikes 10 minutes before they were to be carried out on Thursday after being told 150 people could die.
Announcing Dr Murrison's visit, the FCO said: "The UK has an ongoing diplomatic dialogue with Iran.
"At this time of increased regional tensions and at a crucial period for the future of the nuclear deal, this visit is an opportunity for further open, frank and constructive engagement with the government of Iran.
"Dr Murrison will call for urgent de-escalation in the region and raise UK and international concerns about Iran's regional conduct and its threat to cease complying with the nuclear deal to which the UK remains fully committed."
Dr Murrison, a former naval officer and the MP for South West Wiltshire, was appointed Minister of State for the Middle East in May after Alistair Burt resigned the post in March over Brexit.
US warships and jets in the region have been put on standby after a spy plane was downed by Iran on Thursday
Iran unveils new air defence system capable of targeting fighter jets and drones The incident comes amid heightened tensions between Tehran and Washington.
In recent days, the US confirmed another attempt by Iran to shootdown an American drone last week as well as the successful destruction of one on June 6 by Iranian-aligned Houthi forces in Yemen
Earlier this week, the US announced plans to deploy more than 1,000 additional troops to the Middle East following suspected bomb attacks on two oil tankers.
The Pentagon released photos which it claims proves Iran's Revolutionary Guard were behind the attacks on the ships in the Gulf of Oman.
The Federal Aviation Administration last night prohibited US-registered planes from flying in Iranian-controlled airspace in the Gulf as a direct result of the recent tensions, reports.
Congressional leaders urged caution to avoid escalation and some lawmakers insisted the White House must consult with Congress before taking any actions.
'MAXIMUM PRESSURE' Secretary of State Mike Pompeo and national security adviser John Bolton have advocated hardline policies against Iran.
The Trump administration is engaged in a "maximum pressure" campaign of economic sanctions with a buildup of American forces in the region.
Yesterday, Iran called the sanctions "economic terrorism" insisting the drone had invaded its airspace - near the Kouhmobarak district in south of the country.
It accused the US of "a very dangerous and provocative act" and said it was taking its case to the United Nations.
Iran’s state-run IRNA news agency released this picture - which has now been branded a fake that actually shows a drone being shot down over Yemen. Credit: Islamic Republic News Agency The same photograph - albeit in a wider crop - had previously appeared in a two-year-old report of a spy drone being shot down over Yemen in 2017
Recent US and Iran tensions
May 5: USS Abraham Lincoln carrier strike group and a bomber task force is deployed in Middle East in response to 'a number of troubling and escalatory indications and warnings' by Iran. May 8: Iran vows to enrich its uranium stockpile if world powers fail to negotiate new terms for its nuclear deal. The US responds by imposing sanctions on Iran's metals industry. May 10: The US says it will move a Patriot missile battery into the Middle East to counter threats from Iran. May 24: President Trump says the US will bolster its military presence in the Middle East with an additional 1,500 troops. May 12: The UAE says four commercial ships off its eastern coast "were subjected to sabotage operations," just hours after Iranian and Lebanese media outlets air false reports of explosions at a nearby Emirati port. June 13: Two oil tankers are attacked in the Gulf of Oman - Washington blames Iran while Tehran denies involvement June 18: US sends more than 1,000 additional troops to Middle East citing Iran's 'hostile behaviour' June 20: Iran shoots down American 'spy' drone insisting the aircraft had flown over its airspace - a claim the US denied The drone - which has a wingspan wider than a Boeing 737 - entered Iranian airspace "despite repeated radio warnings", Iran's UN Ambassador Majid Takht Ravanchi claimed.
But the US insists the aircraft was 21 miles from the nearest Iranian territory and flying at high altitude when struck by a surface-to-air missile.
Trump, who has said he wants to avoid war and negotiate with Iran over its nuclear ambitions, appeared to play down the significance of the shootdown.
He cast it as "a new wrinkle ... a new fly in the ointment" while also saying "this country will not stand for it, that I can tell you."
Air Force Lt. Gen. Joseph Guastella, commander of US Central Command air forces in the region, took a more pointed view of the incident.
He said: "This attack is an attempt to disrupt our ability to monitor the area following recent threats to international shipping and free flow of commerce."
The US recently sent an aircraft carrier to the Persian Gulf region and deployed additional troops alongside the tens of thousands already there.
It comes just a week after Iran was accused of planting and detonating mines on two oil tankers in the region.
USA vs Iran: armed forces size comparison President Trump declared that Iran had made a 'very big mistake' by shooting down the drone Credit: Twitter The £102million US surveillance drone was shot down over the Strait of Hormuz Credit: Reuters Iran disputed US claims that the drone was shot down in international air space Credit: AP:Associated Press
US and Iran - a troubled history
Before the 1979 Iranian revolution, Iran was one of America's biggest allies in the Middle East and was led by the US-backed Mohammad Reza Shah Pahlavi. However, since the seismic revolt, Iran has been led by murderous Islamic fundamentalists and tensions with Washington have remained ever since. On November 4, 1979, the Iranian regime took 52 US diplomats hostage in response to President Carter’s administration allowing Iran’s deposed former leader into America. The hostage crisis lasted for 444 days and also included a failed rescue mission which cost the lives of eight US soldiers. In April 1980, the US ended diplomatic relations with Iran – a break which lasted for more than 30 years. In April 1983, Washington blamed the Iranian-funded terror group Hezbollah for carrying out a bombing attack on the American embassy in Beirut, Lebanon. The assault, carried out amid a brutal civil war in Lebanon, killed 17 Americans. In November of that year, two truck bombs in Beruit killed 241 US peace keepers. The US again blamed Hezbollah for the incident. The Clinton White House, in 1995, placed a total embargo on Iran meaning US companies could not trade with the country. And in 2002, George W Bush included the Islamic Republic in his famous “Axis of evil” speech along with North Korea and Iraq. We pay for your stories! Do you have a story for The Sun Online news team? Email us at tips@the-sun.co.uk or call 0207 782 4368. You can WhatsApp us on 07810 791 502. We pay for videos too. Click here to upload yours.