The prime ministers of Canada, the UK and Australia said a Ukrainian passenger plane that crashed Wednesday near Tehran was probably brought down by an Iranian missile, allegations Iran’s government has denied as a lie and “psychological warfare.”

Intelligence from multiple sources, including Canada’s allies, “indicates that the plane was shot down by an Iranian surface-to-air missile,” Prime Minister Justin Trudeau told reporters in Ottawa Thursday, calling for an international probe of the disaster. “This may well have been unintentional.”

More than a third of the 176 people aboard Ukraine International Airlines Flight 752, which plunged from the sky about two minutes after a pre-dawn takeoff, were from Canada. The Boeing 737-800 was on fire, according to witnesses on the ground and in other aircraft who were cited in a preliminary Iranian report on the crash.

UK Prime Minister Boris Johnson issued a statement earlier Thursday saying there is evidence Flight 752 was shot down by an Iranian surface-to-air missile.

“We are working closely with Canada and our international partners and there now needs to be a full, transparent investigation,” Johnson said.

In Australia on Friday, Prime Minister Scott Morrison said in a radio interview that his country had intelligence that an Iranian missile had shot down the jetliner. In another radio interview, he said he had been briefed by Trudeau and described the episode as “a terrible accident.” In Ukraine, President Volodymyr Zelenskiy said while a missile hit hadn’t been ruled out, it also hadn’t been confirmed, “as of today.”

Whether accidental or intentional, a shoot-down would echo two other instances of surface-to-air missiles striking civilian jets. In 2014, pro-Russian rebels in Ukraine fired on and destroyed a Malaysian Air jetliner. In 1988, an Iranian airliner was felled by a US cruiser after being mistaken for a hostile aircraft following a skirmish with Iranian boats.

President Donald Trump, speaking to reporters in Washington on Thursday, said, “I have my suspicions” about why the plane went down but said he didn’t say what those suspicions are.

“It was flying in a pretty rough neighborhood,” Trump said. “Somebody could have made a mistake.”

Two surface-to-air missile launches were detected by a US spy satellite from an Iranian battery near the airport minutes after the jet took off, followed by an explosion near the plane, said a person familiar with the investigation who spoke on the condition of anonymity.

The Russian-made SA-15 missile, also known as a Gauntlet or a Tor, are suspected of being involved. They are short-range weapons designed to attack planes, helicopters and other airborne targets.

The New York Times reported that it had obtained a video that appears to show an Iranian missile hitting a plane near the Tehran airport. The video shows a small explosion occurring when a missile struck the jet, which didn’t explode, according to the Times.

Iran’s State-run IRNA news service denied that a missile hit the plane, citing a statement from Iranian government spokesperson Ali Rabiei.

“News of two missiles hitting the Ukrainian plane has circulated in media with much fanfare, in a calculated and well-known manner and as part of a psychological warfare,” the report said. “Future will show that these claims are empty of truth and no one will bear responsibility for this big lie.”

Ali Abedzadeh, head of Iran’s Civil Aviation Organization, CAO, said “it’s not possible” for an Iranian rocket to have hit the plane.

“There’s a very defined relationship in Iran between military and civilian structures and it’s based on the regulations of the international civil aviation authority to which we comply, like all other countries,” he said in an interview on Iranian TV.

Boeing rose as much as 3.1% and was up 1.5% to $336.34 Thursday in New York. If the plane was brought down by a missile strike, it could rule out a mechanical failure that would affect other Boeing aircraft.

“Our country is interested to find out the truth,” the Ukrainian president’s office said in a statement. “So we address all Ukraine’s international partners: if you have evidences that can help the investigation, please provide them.”

It said 45 Ukraine experts were working in Iran on the investigation and there are “several versions” for the cause under consideration.

Iranian President Hassan Rouhani spoke by phone with his counterpart Zelenskiy on Thursday and agreed to form a task force involving their transport officials and foreign ministries, the semi-official Fars news agency reported, citing Rouhani’s deputy head of communications. Zelenskiy will discuss the crash with US Secretary of State Michael Pompeo, the Ukrainian president said on Facebook.

The US intelligence assessment is consistent with what some aviation accident experts have said. The apparent rapid spread of the fire combined with the sudden halt of radio transmissions from the plane after a normal climb aren’t consistent with previous crashes, said Jeffrey Guzzetti, the former head of accident investigations at the Federal Aviation Administration.

While Iranian officials initially said they suspected a problem with one of the plane’s engines, they retracted that in a preliminary report issued Thursday. The government also took the unusual step of setting up an investigative group to examine whether “any unlawful actions” initiated the fire on the plane, the preliminary report said.

Iran notified the International Civil Aviation Organization, an arm of the United Nations, about the crash, which should trigger involvement of other nations in the investigation, including the US, the agency said in a press release Thursday.

Under rules known as Annex 13, the nation in which a crash occurs usually is in charge of an investigation. Other nations are permitted to take part, such as the country in which the plane was made. Since Boeing manufactured the Ukrainian jet, the US National Transportation Safety Board would have a right to participate.

“Ukraine, as the operator country of the plane, is obliged to cooperate with us and share the plane’s necessary data for investigation,” Abedzadeh, the Iranian aviation official, said in a TV interview Thursday. “Others can also join in investigations.”

In a statement on Thursday evening, Canada’s Transportation Safety Board said it had “been invited by the Aircraft Accident Investigation Bureau of the Islamic Republic of Iran to attend the accident site. We have accepted this invitation and we are making arrangements to travel to the site.”

Abedzadeh said France, where portions of the engines were made, and the US had been notified and could take part.

“France, Canada and the NTSB of the United States have expressed their readiness and introduced their representatives for cooperation,” he said.

It remains unclear whether NTSB will send a representative to the Iran because US law restricts travel to that country and the exchange of certain data. The agency said in a statement on Thursday night that it had “designated an accredited representative to the investigation of the crash.”

The US Treasury has granted waivers for US investigators to work in Iran in the past, but it has been a cumbersome process. Also, the NTSB has at times declined to send investigators to countries it deems unsafe.