Iran's civil aviation authority has confirmed that two missiles were launched at a Ukrainian passenger jet just after it took off from Tehran's international airport bound for Kyiv on January 8.
The authority said in a second preliminary report on the crash, which killed all 176 passengers on board, that it was still assessing the disaster.
"Investigators...discovered that two Tor-M1 missiles... were fired at the aircraft," the report said.
The Tor-M1 is a short-range surface-to-air missile originally developed by the former Soviet Union and designed to target aircraft or cruise missiles.
The Iranian statement confirmed last week's report in The New York Times which included a video recording that appears to show two missiles being fired at the Ukrainian plane.
Iranian officials have said that air defenses on high alert during heightened tensions after Iranian missile strikes "unintentionally" fired antiaircraft missiles at the Ukraine International Airlines Boeing 737-800.
The Iranian report also said Tehran has requested equipment from U.S. and French authorities to download data from the flight recorders but it has not yet received a positive response.
Canada, Ukraine, and other nations who had citizens on the flight have asked Iran to send the flight data and voice recorders to experts abroad for analysis.
"We hope that we can go a little further than just political discussions and discuss practical problems; among them in particular is the return of the black boxes," Ukrainian Foreign Minister Vadym Prystayko told reporters on January 20 after a meeting in Kyiv with the Iranian Minister of Roads and Urban Development Mohammad Eslami.
Afghanistan, Britain, Canada, Ukraine, and Sweden -- countries whose nationals were killed in the crash -- issued a joint statement calling for a "thorough, independent, and transparent" investigation. Most of the victims were Iranian and Canadian citizens.
Canada has said France would be the best place to send the black boxes because it was one of the few nations with the ability to read them. However, Tehran has given mixed signals about whether the black boxes would be handed over.
The Iranian official leading the investigation, Hassan Rezaeifar, was quoted by the Iranian media as saying the country might eventually send the black boxes abroad, adding, "But, as yet, we have made no decision."