In this photo released by the official website of the office of the Iranian Presidency, President Hassan Rouhani speaks in a cabinet meeting in Tehran, Oct. 2, 2019.
FILE - Iranian President Hassan Rouhani, pictured in Tehran, Oct. 2, 2019, said Saturday that he was saddened by the mistaken shootdown of a Ukrainian jet and expressed "my deep condolences to the families of victims of this painful catastrophe."

In the face of mounting evidence, Iran acknowledged Saturday that it had shot down a Ukrainian jetliner by accident this week after it took off in Tehran, killing all 176 people aboard. 

Once Iran made the admission, after three days of denying it was responsible, the reaction came swiftly, from Iran and around the world. 

From Iran: 

General Amir Ali Hajizadeh, the head of the Islamic Revolutionary Guard Corps’ aerospace division, said his unit accepted full responsibility for the shootdown. In an address broadcast by state TV, he said that when he learned about the downing of the plane, "I wished I was dead." 

Hajizadeh said the missile operator mistook the 737 for a cruise missile and didn’t obtain approval from his superiors because of disruptions in communications. 

"He had 10 seconds to decide. He could have decided to strike or not to strike and under such circumstances, he took the wrong decision," Hajizadeh said. 

Ayatollah Ali Khamenei, Iran’s supreme leader, expressed his "deep sympathy" to the families of the victims and called on the armed forces to "pursue probable shortcomings and guilt in the painful incident." 

President Hassan Rouhani acknowledged his country’s responsibility. 

"Iran is very much saddened by this catastrophic mistake and I, on behalf of the Islamic Republic of Iran, express my deep condolences to the families of victims of this painful catastrophe," the president said. 

Rouhani added he had ordered "all relevant bodies to take all necessary actions [to ensure] compensation" to the families of those killed. 

A leader of Iran’s opposition Green Movement, Mehdi Karroubi, called on Khamenei to step down over the handling of the downed airliner. 

FILE - Ukrainian President Volodymyr Zelenskiy, right, leads a meeting of the emergency response team on the crash of the Ukraine International Airlines plane in Iran, in Kyiv, Ukraine, Jan. 9, 2020.

From Ukraine: 

Ukraine’s President Volodymyr Zelenskiy thanked the U.S, Britain, Canada and others for information about the crash. He said it "undoubtedly helped" push Iran to acknowledge its responsibility. Zelenskiy said the crash investigation should continue and the "perpetrators" should be brought to justice. 

"It’s absolutely irresponsible," Ukraine International Airlines Vice President Ihor Sosnovskiy told reporters. "There must be protection around ordinary people. If they are shooting somewhere from somewhere, they are obliged to close the airport." 

From Canada: 

Canadian Prime Minister Justin Trudeau demanded Iran provide "full clarity" on the downing of the plane, which Ottawa said had 57 Canadian citizens aboard. 

FILE - Canadian Prime Minister Justin Trudeau speaks during a news conference, Jan. 9, 2020, in Ottawa, Ontario.

"What Iran has admitted to is very serious. Shooting down a civilian aircraft is horrific. Iran must take full responsibility," Trudeau told a news conference in Ottawa. "Canada will not rest until we get the accountability, justice and closure that the families deserve." 

Foreign governments condemned the downing of the plane, with Ukraine demanding compensation. Canada, Ukraine and Britain, however, called Tehran’s admission an important first step. 

The Associated Press, Agence France-Presse, and Reuters contributed to this report.