Iran on Friday termed reports that it had shot down a Ukrainian commercial airliner in Tehran as “lies” concocted by the United States as part of the latter’s “psychological operations” against Iran.

“Today, in a very well-calculated move in psychological operations as quoted by an informed source of Pentagon… has published news pompously that two missiles hit the Ukrainian plane. This is a lie and nobody will claim responsibility of the big lie,” said a statement from the Iranian government published on the state-run IRNA news agency’s website.

The statement also recommended the US government to “attend to the results of the investigation committee instead of lying and developing psychological operations”.

“It is regrettable that the US government's psychological operations system and its informed or uninformed allies are adding salt to the pains of the bereaved families with these lies and victimise (sic) affected families to reach their goals in the psychological operations,” the statement reads.

Earlier today, several Western leaders followed President Trump and unnamed Pentagon officials in alleging that the Ukrainian aircraft was “unintentionally” hit by surface-to-surface missiles from Iran when it launched ballistic missiles at two US bases in Iraq to avenge the killing of its top general in an American airstrike.

Iran invites Boeing, other countries to join investigation

Following these accusations, Iran invited Boeing to take part in the crash investigation, state media reported Friday.

Read more: US-Iran conflict: Before and after the killing of Gen Soleimani

The state-run IRNA news agency quoted a foreign ministry spokesman as saying Iran “has invited both Ukraine and the Boeing company to participate in the investigations”.

The spokesman, Abbas Mousavi, said it will also welcome experts from other countries whose citizens died in the crash.

Canadian and British officials also said it was “highly likely” that Iran shot down the Boeing 737 that crashed near Tehran on Wednesday.

Canadian Prime Minister Justin Trudeau, whose country lost at least 63 citizens in the downing, said we have intelligence from multiple sources including our allies and our own intelligence.

“The evidence indicates that the plane was shot down by an Iranian surface-to-air missile,” he said. UK Prime Minister Boris Johnson and Australian Prime Minister Scott Morrison offered similar statements.

Morrison also said it appeared to be a mistake. “All of the intelligence as presented to us today does not suggest an intentional act,” he said.

Mousavi said Iran asks Canada’s prime minister and any other government to “provide any information they have to the investigation committee”.

Iranian officials had already ruled out a missile strike, and initially said the plane appeared to have crashed because of technical difficulties.

A preliminary Iranian investigative report released on Thursday said that the airliner pilots never made a radio call for help and that the aircraft was trying to turn back for the airport when the burning plane went down.

The Iranian report suggested that a sudden emergency struck the Boeing 737, operated by Ukrainian International Airlines, just minutes after taking off from Imam Khomeini International Airport in Tehran early on Wednesday.

Before the US assessment, Iran's state-run IRNA news agency quoted Hasan Rezaeifa, the head of the civil aviation accident investigation commission, claiming that the topics of rocket, missile or anti-aircraft system is ruled out.

US, Canada, France to be part of probe

Later in the day, France, Canada and the United States confirmed they are sending their representatives to Tehran to become part of the crash investigations.

Iranian state media also reported that United States, Canadian and French representatives will travel to Tehran to attend meetings for the Iran-led investigation into the Ukrainian airliner incident.

"As soon as they will arrive they will attend the meetings to investigate reasons for the crash," IRNA reported.

The US accident investigator, the National Transportation Safety Board (NTSB), had been in talks with the State Department and the Treasury Department about traveling to Iran to inspect the US-built aircraft and working with Iranian authorities despite US economic sanctions against that country.

In a statement on Thursday, the NTSB said it continues to monitor the situation surrounding the crash and evaluate its level of participation in the investigation.