BREAKING: Ukraine-bound Boeing airliner was shot down by Iran missile.

Aircraft parts from the wreckage of a Boeing Co. 737-800 aircraft, operated by Ukraine International Airlines, which crashed shortly after takeoff lie on the ground near Shahedshahr, Iran, on Wednesday, Jan. 8, 2020. Ali Mohammadi/Bloomberg via Getty Images

Spy satellite imagery suggests that a Ukraine-bound Boeing passenger airliner that crashed shortly after takeoff from Tehran was shot down by an Iranian missile, killing all 176 people aboard, NBC News reported Thursday.

Other reports also said it seemed like the airliner was shot down on Wednesday local time by a missile fired by mistake by Iranian forces, which shortly before the crash had launched missile attacks on bases in Iraq that house U.S. and coalition forces.

The reports came as President Donald Trump said he does not believe mechanical failure caused the crash.

Iranian officials had originally suggested that the Boeing 737-800 fell from the skies because of a technical problem.

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

“I have a feeling that — it’s just some very terrible, something very terrible happened, very devastating,” Trump added.

Most of the passengers on the flight were from Iran and Canada. Other passengers came from countries including Sweden and Ukraine.

A reporter for CTV said Canadian government sources believe the shoot-down reports are credible.

Newsweek noted that images that began circulating on Wednesday show what looked to be fragments of a Tor M-1 missile that were said to be found in a Tehran suburb.

Iran’s head of civil aviation dismissed such reports as “illogical rumors,” according to an state-run news outlet.

Sen. Jim Inhofe, R-Okla., said, “It sounds pretty convincing that the plane that was shot down … by Iranians.”

Asked what the U.S. response should be if true, Inhofe paused and then said, “I don’t want to interfere with the decisions that are now being made by the president.”

“I’m quite sure I’ll be talking to him because we talk on a regular basis about things like that.”

Sen. Lindsey Graham, R-S.C., said that it Iranian missiles had shot down the plane “it would be an outrage.”

“What I would do if I were the president would be to reach out to the Canadian people and the prime minister and try to rally the world around the idea that we shouldn’t accept 40 more years of state-sponsored terrorism,” Graham said.

Iran’s civil aviation authority, which did not immediately respond to a request for comment from CNBC, said earlier Thursday that the plane departed Tehran’s Imam Khomeini airport at 6:13 a.m. local time on Wednesday and lost communication with air traffic controllers five minutes later.

Ali Abedzadeh, head of the National Aviation Authority, said in a statement that eyewitnesses had reported that the Kyiv-bound plane was on fire immediately before the crash.

Aviation safety experts, including former government crash investigators, told CNBC that the sudden loss of communication and lack of a distress signal were highly suspicious signs.

The crash occurred hours after Iran launched retaliatory missile strikes on U.S. positions in Iraq for the killing of Gen. Qasem Soleimani. The timing prompted speculation that a stray Iranian missile may have downed the passenger plane.

Under international law, the country in which the crash occurs leads the investigation, but because the plane was U.S.-made, federal investigators and Boeing would normally be involved.

An Iranian official told local news media on Wednesday that Iran did not plan to share the information with Boeing or the U.S.

The country may send the recovered black boxes, which contain flight data and cockpit voice recordings, abroad for analysis but Iran has not yet said where they could be sent. Iranian aviation officials said black boxes that were recovered from the plane were damaged by fire in the crash.

Determining the cause of plane crashes can take more than a year.

Ukrainian President Volodymyr Zelenskiy vowed to uncover the “truth,” and said investigators from Ukraine had already traveled to Iran to assist the inquiry there.

Ukraine’s embassy in Iran originally said an engine problem likely caused the crash and ruled out terrorism or a rocket as possible causes. But that statement later was taken down from the embassy’s website.

The plane was the model that preceded the Boeing 737 Max, the model that has been grounded worldwide since mid-March in the wake of two fatal crashes. The 737-800 was delivered new to Ukrainian International Airlines in 2016, and its crew included three experienced pilots, according to the carrier.

Boeing said in a statement that it is “ready to assist in any way needed.”

Boeing shares rose after news broke of U.S. government officials’ comments that a missile could have been involved in the crash.

Boeing has struggled to regain its footing from the fallout of the twin Max crashes that killed 346 people. Boeing’s former CEO was fired and the manufacturer suspended production of the best-selling etliners.