Iran has accepted that it was responsible for shooting down a Ukrainian jet and killing all 176 people on board for the first time.
President Hassan Rouhani said an investigation had found that “missiles [were] fired due to human error”.
He said it was an “unforgivable mistake”.
Rouhani said on Twitter: “Armed Forces’ internal investigation has concluded that regrettably missiles fired due to human error caused the horrific crash of the Ukrainian plane & death of 176 innocent people.
“Investigations continue to identify & prosecute this great tragedy & unforgivable mistake.”
Iran had previously categorically denied all accusations that they were responsible.
Even as recently as Friday, despite new footage emerging, the country’s civil aviation organisation chief, Ali Abedzadeh said: “The thing that is clear to us and that we can say with certainty is that this plane was not hit by a missile.”
The Ukraine International Airlines passenger plane had been on route to Kiev from Tehran. It had 82 Iranians, 63 Canadians and four Britons on board.
The flight took off just hours after Iran had carried out missile strikes on two airbases housing US forces in Iraq in retaliation for the assassination of General Qasem Soleimani.
Iranian military said the plane had flown near a “sensitive military centre” of the Revolutionary Guards.
In a statement it said that it “was at its highest level of readiness” due to the tensions with the US.
“In such a condition, because of human error and in an unintentional way, the flight was hit,” it added.
Iran’s foreign minister Javad Zarif apologised to the families of the victims but portioned some of the blame to the US.
“Human error at a time of crisis caused by US adventurism led to [this] disaster,” he said.
In the wake of the news, Canadian prime minister Justin Trudeau said: “Our focus remains closure, accountability, transparency, and justice for the families and loved ones of the victims. This is a national tragedy, and all Canadians are mourning together.
“We will continue working with our partners around the world to ensure a complete and through investigation, and the Canadian government expects full cooperation from Iranian authorities.”
Ukraine’s President Volodymyr Zelenskiy demanded a “full admission of guilt”.
He said: “We expect assurances of readiness for a full and open investigation from Iran, bringing those responsible to justice, repatriation of bodies of the dead, payment of compensation, official apologies through diplomatic channels.”