The guard's aerospace commander, Amirali Hajizadeh, said on state television Saturday, "I take full responsibility and I will obey whatever decision is taken." He said he "wished" he "were dead" when he learned about the fate of the aircraft.
"That night we had the readiness for all-out war," Hajizadeh said. He added that the Revolutionary Guard asked that commercial fights be canceled but that the request was not adhered to.
Earlier Saturday, Ukraine's president had called for a full admission of guilt for the downing of the plane that killed all 176 people aboard.
Volodymyr Zelenskiy said he also wanted "a full and open investigation, bringing those responsible to justice, the return of the bodies of the dead, the payment of compensation, official apologies through diplomatic channels."
Zelenskiy said later that Iran has provided enough "photos, videos and other materials" from the crash "to see that the investigation will be carried out objectively and promptly."
Ukrainian experts in Iran have received "full cooperation" from Iran and have been given access to the crash site and the plane's data recorders, Ukrainian Foreign Minister Vadym Prystaiko said. He said Ukraine's team has "access to the recordings of conversations between the dispatchers of the flight control center at the airport in Tehran and our pilots."
Canadian Prime Minister Justin Trudeau has demanded "transparency and justice for the families and loved ones of the victims." Many of the passengers were Iranian-Canadians. "This is a national tragedy, and all Canadians are mourning together."
Iran has admitted that its military made a horrendous miscalculation when it shot down a Ukrainian jetliner earlier this week in the outskirts of Tehran, killing all 176 people aboard.
Three days after Iran mistakenly shot down the Ukrainian jetliner in the outskirts of Tehran, killing all 176 people aboard, Iranian President Hassan Rouhani said on Twitter that Iran "deeply regrets this disastrous mistake."
Rouhani added that an Iranian military internal investigation found 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."
Iranian Foreign Minister Mohammad Javad Zarif posted on Twitter Saturday: "A sad day. Preliminary conclusions of internal investigation by Armed Forces: Human error at time of crisis caused by US adventurism led to disaster. Our profound regrets, apologies and condolences to our people, to the families of all victims, and to other affected nations."
The Ukrainian International Airlines flight was mistaken for a "hostile target" as it made a turn toward a "sensitive military center" of the Revolutionary Guard," according to a military statement carried on state media. "In such a condition, because of human error and in a unintentional way, the flight was hit."
The military said it had been at its "highest level of readiness" amid heightened tensions with the United States.
The downing of the Ukrainian International Airlines jetliner, a Boeing 737, happened just hours after Iran launched a ballistic missile attack on Iraqi bases housing U.S. soldiers in response to last week's U.S. drone attack that killed Iranian Quds Force commander Qassem Soleimani.
Iran had initially denied that it was responsible for the downing of the jet, however, U.S. and Canadian intelligence said they believed Iran shot down the aircraft.
U.S. President Donald Trump attacked Democratic lawmakers on Twitter Saturday, questioning their response to the U.S. killing of the Iranian commander.
"Where have the Radical Left, Do Nothing Democrats gone when they have spent the last 3 days defending the life of Qassem Soleimani, one of the worst terrorists in history ..." who "was also looking to do big future damage!"
Trump's attack on Democrats came as he and senior members of his administration faced persistent questions from Democrats about his decision to order the killing of Soleimani.
Like the Democrats, lawmakers from Trump’s own Republican Party are also applying increasing pressure on Trump and his senior advisers to disclose more information about the intelligence they had that indicated Soleimani was planning imminent attacks on American personnel in the region.
Trump administration officials continued to offer a series of explanations Friday to justify the killing, including a claim that Iranian militants had planned attacks on four U.S. embassies. The claim conflicts with intelligence assessments from other top Trump administration officials.
An unnamed Trump administration official said Saturday that Iran's accidental downing of the jetliner was "reckless" and "again had devastating consequences." The official added: "It is more important now than ever that Iran abandons its reckless ambitions and starts behaving like a normal country."
Payman Parseyan, a prominent Iranian-Canadian told the Associated Press, "Iran is responsible for its own military defense equipment. While it has the right to defend itself, as it should to protect its own people, it should also have the responsibility with that right to make sure their defensive systems aren't targeting civilian aircraft."
The flight was en route to the Ukrainian capital Kyiv, a connection stop for many Iranian-Canadians and Iranian students studying in Canada. There were 57 Canadians among the passengers.