Iran's elite Revolutionary Guard has admitted it "unintentionally" shot down a Ukrainian passenger jet with a short-range missile on Wednesday, killing all 176 on board.

Senior figures in Tehran claimed the US was partly responsible for the crash, which happened hours after Iran launched ballistic missiles at two US bases in Iraq to avenge the killing of its top military general in an American airstrike.

Iran's Supreme Leader Ayatollah Ali Khamenei expressed "deep sympathy" to the victims, and said the armed forces must "pursue probable shortcomings and guilt in the painful incident".

🔴 Statement here from the General Staff of the 🇮🇷 Iranian Armed Forces admitting that they accidentally shot down the Ukrainian plane #PS752 pic.twitter.com/2iljI2sdkH — Mark Stone (@Stone_SkyNews) January 11, 2020

The commander of the Revolutionary Guard's air force, General Amir Ali Hajizadeh, appeared on state TV to apologise to the nation and take full responsibility for the downing.

He said the Ukrainian plane was "misidentified as a cruise missile" by an air defence operator but admitted he had told his superiors about the "unintentional... attack" on Wednesday


He said it had been downed by a "short-range missile", adding: "I wish I could die and not witness such an accident."

He partly blamed the US, saying it had spiked tensions, and that Iran had been ready for "all-out war" at the moment the missile was fired at the Ukrainian jet.

Iranian foreign minister Javad Zarif ultimately blamed "US adventurism".

The Iranian Fars news agency said Ayatollah Khamenei was informed about the downing on Friday and ordered that the information should be publicly announced.

Image: Plane engine among debris in Iran

He said: "Having been informed about... the crash of the Ukrainian passenger plane and confirmation of the human error... the tragedy of deaths of passengers in this sad incident became a lot more severe for me.

"It is imperative... to offer my deepest sympathies and sincerest condolences. I strongly advise the armed forces headquarters to pursue shortcomings and possible guilt in this painful incident... I demand... follow-ups... for prevention of similar incidents in the future. May God show compassion and mercy to the victims and give patience and grace to their families."

Iranian President Hassan Rouhani tweeted his condolences to the victims, saying: "The Islamic Republic of Iran deeply regrets this disastrous mistake."

The US and Canada had previously suggested that Iran had accidentally downed the Ukrainian jet, citing intelligence, but Iran denied any involvement.

Tehran went as far to say the accusations were "psychological warfare against Iran".

On Friday, Hamid Baeidinejad, the Iranian ambassador to the UK, told Sky News that he was confident there had not been a missile strike that caused the plane to come down.

On Saturday morning, he apologised, tweeting: "In my statement yesterday to the UK media, I conveyed the official findings of responsible authorities in my country that missile could not be fired and hit the Ukrainian plane at that period of time. I apologise and regret for conveying such wrong findings."

Iranians vented their anger about what had happened on social media, which is restricted in Iran, with several calling for the resignations of senior officials, and even spoke out via semi-official news agencies.

There have also been protests outside Tehran's Amir Kabir university, with videos posted on social media showing hundreds of people chanting for the supreme leader to resign.

According to the Iranian Fars news agency, the demonstrators ripped up pictures of commander Qassem Soelimani, whose killing by the US prompted Iran to launch strikes against Iraqi air bases housing American personnel.

Iran ambassador rejects 'absurd' crash claims

Ali Ansari, a moderate cleric, said: "It is a national tragedy. The way it was handled and it was announced by the authorities was even more tragic."

Mira Sedaghati, from Tehran, told Reuters: "They were so careful not to kill any American in their revenge for Soleimani. But they did not close the airport? This shows how much this regime cares for Iranians."

Their comments came after Iran held three days of state-organised funeral procession for Gen Soleimani, which were attended by millions.

Four British nationals were among those killed when Ukraine International Airlines flight PS752 crashed shortly after leaving Tehran International Airport.

Sky's Middle East correspondent Mark Stone said: "It is remarkable that Iran is admitting this. Playbook Iran would suggest that they wouldn't. They tend to deny, deny, deny.

"But in this instance the evidence was so overwhelming, and when you combine that with the intelligence assessments that were coming over from America, from Canada and from others, and that Iran was now allowing Canadian experts into the country to assess the black box and some of the damage, it was going to become clear that there was no other plausible reason for this."