Iran has denied reports that one of its missiles hit a Ukrainian passenger airplane.
The Ukraine International Airlines jet crashed earlier this week near Tehran, killing all 176 people on board.
Iranian officials called on the United States and Canada Friday to share any information they have on the crash.
The plane broke up just hours after Iran launched missiles at two air bases in neighboring Iraq. The bases housed U.S. troops. Iran launched the attacks to answer the killing of its top general in a U.S. airstrike last week.
The downed aircraft was carrying 63 Canadians. On Thursday, Canadian Prime Minister Justin Trudeau said, The evidence indicates that the plane was shot down by an Iranian surface-to-air missile. He noted the information came from several intelligence sources.
U.S. officials said that Iran might have mistakenly identified the Boeing 737 as a threat.
Ali Abedzadeh is head of Iran's national aviation office. He said Friday, What we can say with certainty is that no missile hit the plane. He urged Western nations to, in his words, come and show their findings to the world.
Western governments may not be ready to share the information because it comes from highly classified intelligence sources. However, The Associated Press, The New York Times and other media companies released videos appearing to show something hitting a plane near Tehran's main airport.
In one video from The Associated Press, someone off camera says: The plane has caught fire... In the name of God, the compassionate, the merciful. God, please help us. Call the fire department! The comments were made in Farsi, the official language of Iran.
Shortly after the crash, Iran reported the recovery of the plane's flight recorders -- or black boxes.
Abedzadeh announced, We prefer to download the black boxes in Iran. But if we see that we can't do that because the boxes are damaged, then we will seek help.