Canadian Prime Minister Justin Trudeau said Thursday that several intelligence sources, including Canadian, indicated that the "Boeing 737" plane that crashed near Tehran on Wednesday "was shot down by an Iranian surface-to-air missile."
"We have information from multiple sources, including those from our allies and our devices ... indicating that the plane was shot down by an Iranian surface-to-air missile ... maybe it was not intentional," Trudeau told a news conference.
Shortly before that, US President Donald Trump said that he had "doubts" about the causes of the crash of a Ukrainian passenger plane after take off, while US media reported that intelligence services were becoming increasingly convinced that the plane had accidentally shot down an Iranian missile.
As for the British Prime Minister, Boris Johnson, he stated that there is evidence that the plane was shot down by a surface-to-air missile that may have been launched unintentionally.
About fifty aviation experts and a Ukrainian security official arrived in Tehran on Thursday morning to participate in the investigation, including reading the data of the black boxes that the Iranian authorities had found at the site of the disaster.
US officials had expressed confidence that the Iranian air defenses brought down the crashed Ukrainian plane in error. Reuters news agency quoted them as saying that they had concluded that the plane was shot down by an Iranian missile based on satellite data and government officials.
The Iranian authorities responded to the hypothesis that the plane was struck by a missile, saying that it was "meaningless rumors". The Iranian Civil Aviation Administration said that there had been extensive research into the crash zone, and that there was nothing suspicious there.
And the commission added that the joint fact-finding committee with Ukraine completely excludes the hypothesis of shooting down the plane with a missile, considering that what is reported on it is "just false rumors whose aim is political."
For its part, the Iranian Foreign Ministry invited Ukraine and Boeing Company to participate in the investigations into the crash, and said that Tehran had started its investigations according to international decisions and standards.
As for the head of the Iranian Civil Aviation Administration, he said that his country has invited France and the United States to participate in the investigation into the crash, stressing that the responsibility for reading the black box rests with his country and will be carried out in the presence of Ukrainian experts.
The aviation accident investigation department in Iran said that a technical malfunction of the Ukrainian plane led to the ignition of the engine and its downfall. "We are ready to disclose our documents to the media," she added.
The office of Iranian President Hassan Rouhani confirmed that he had agreed with his Ukrainian counterpart to task the foreign ministries of the two countries to facilitate the investigation through the joint committee between the two countries.
On Wednesday, a Ukrainian "Boeing 737" airliner crashed, killing 176 people, including 82 Iranians and 63 Canadians. On Thursday, Ukrainian officials put forward three hypotheses explaining the cause of the crash, which was traveling from Tehran to Kiev.
The Ukrainian National Defense and Security Council said in a statement, that the plane may have been subjected to a terrorist act, or hit a surface-to-air missile, adding that the third reason that might explain the crash was the engine's explosion due to technical problems.
Earlier Thursday, a preliminary report revealed to the Iranian Civil Aviation Administration, that the Ukrainian plane turned to return to the airport from which it took off in Tehran after a fire broke out and faced a problem.