After maintaining for days that there was no evidence to show one of its missiles had struck the plane, the Iranian military said it was an accident caused by human error.
Iran announced early Saturday that it had accidentally shot down a Ukrainian passenger jet, blaming it on human error because of what it called the plane’s sharp, unexpected turn toward a sensitive military base, according to a statement issued by the country’s military.
The announcement reversed Iran’s claims that mechanical issues caused the crash of the aircraft, which killed all 176 people aboard. It had persistently denied that Iranian military defenses had downed the aircraft, a Boeing 737-800.
International pressure had been building on Iran to take responsibility. American and allied intelligence assessments have said that Iranian missiles brought down the plane, most likely by accident, amid the heightened tensions between the United States and Iran.
Suspicions that an Iranian missile had brought down the plane began immediately after Wednesday morning’s crash — just hours after Iran fired missiles at two bases in Iraq housing American forces.
The Iranians asked the National Transportation Safety Board to help with the investigation, and the State Department granted waivers to allow the American agency to help. A senior administration official said Friday that he thought the Iranians wanted American investigators there to keep up the appearance that they did not know what had caused the crash.
An Iranian report released on Thursday said that the plane, bound for the Ukrainian capital, Kyiv, was in flames before it hit the ground but sent no distress signal.
Video verified by The New York Times and published on Thursday appeared to show a missile fired from Iranian territory hitting the plane. The video showed a small explosion as the plane flew above Parand, a city near the airport — where it stopped transmitting its signal before it crashed. The plane turned back toward the airport before it exploded and crashed, other videos verified by The Times showed.
When Iran began firing missiles early on Wednesday in retaliation for the killing of General Suleimani by the United States in Baghdad, international airlines rerouted flights away from Iran, and the Federal Aviation Administration barred American carriers from the airspace in the region.
After the crash, experts raised questions about why the Iranian authorities had not stopped flights in and out of Tehran.
In Iran, a debate over how much blame the government bears threatened to destroy the national solidarity that followed the country’s conflict with the United States. Many Iranians said that their anger over the lack of accountability at the highest levels of government had quickly returned.
On Friday, Secretary of State Mike Pompeo said that the United States and its allies had intelligence showing that the passenger jet had been shot down. He was the first American official to publicly confirm the intelligence assessments.
Prime Minister Justin Trudeau of Canada, citing a preliminary review of the evidence, called for a full investigation “to be convinced beyond all doubt.” The jetliner was carrying 57 Canadians among its 176 passengers and crew.
“We recognize that this may have been done accidentally,” Mr. Trudeau said at a news conference in Ottawa. “The evidence suggests very clearly a possible and probable cause for the crash.”
President Volodymyr Zelensky of Ukraine made clear on Friday that Western governments had not initially shared the evidence underpinning their assessments that Iran had brought down the Ukrainian jet, though later a spokeswoman said that American officials had handed over more information.
Ukrainian officials also analyzed the plane’s flight pattern on Friday and determined it had stayed within the normal corridor for flights out of Tehran’s Imam Khomeini International Airport, Ukraine’s foreign minister, Vadym Prystaiko, said at a news conference.
“Our goal is to ascertain the undeniable truth,” Mr. Zelensky said in a statement on Friday. “We believe this is the responsibility of the whole international community before the families of the dead and the memory of the victims of the catastrophe.”