Multiple US outlets are reporting that Ukrainian International Airlines Flight 752 was shot down by a surface-to-air missile in Iran.

However, Iran continues to maintain that its missile defense system is not to blame.

An Iranian official said Thursday that it was "scientifically impossible" for one of their defense missiles struck the plane because of its altitude and the fact that no other planes in the area were harmed.

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Despite a wave of evidence coming out Thursday suggesting that Ukrainian International Airlines Flight 752 was hit by a surface-to-air missile before it crashed outside Tehran, Iranian officials continue to maintain they're not to blame.

Following new reports, an Iranian aviation official said it's "scientifically impossible" that one of their defense missiles hit the plane because it was flying at an elevation of 8,000 feet, the Fars News Agency reported.

However, that would make it well within the range of the 29 Tor M1 missile defense batteries that Iran purchased from Russia in 2005, which can hit targets of up to 20,000 feet in altitude.

An English translation of the above tweet. Fars News Agency/Twitter

The official also pointed out that several other commercial jets were flying at that altitude at the same time, seeming to suggest that because none of the others were hit that the missile defense system wasn't triggered.

The crash of the Boeing 737 came amid increased tensions between the US and Iran. Just a few hours prior, Iran conducted retaliatory airstrikes against US military installations in Iraq. The strikes were meant to avenge the death of Iran's top general, Qassem Soleimani, who was killed in a US airstrike ordered by President Donald Trump on January 3.

Justin Bronk, a research fellow at the British defense think tank Royal United Services Institute, tweeted Thursday that if the allegations are true, it shows "staggering incompetence and carelessness" to mistakenly fire at a commercial jet.

"There is no excuse. Doesn't matter [if] it was during a US-provoked standoff," he said.

All 176 people on board, who were flying to Kyiv, Ukraine, were killed. They included 82 Iranians, 63 Canadians, 11 Ukrainians, 10 Swedes, 4 Afghans, 3 Germans, and 3 Brits, according to Ukraine's foreign minister.

Many of those aboard held dual citizenship with Iran. But because Iran doesn't recognize dual citizenship, it's own breakdown of the demographics of those aboard show the flight was predominantly Persian. The initial government report said that 146 Iranians were killed, in addition to 11 Ukrainians, 10 Afghans, 5 Canadians, and 4 Swedes.

On Wednesday, The New York Times spoke to a Canadian source who said that Western intelligence agencies had no proof of the plane being shot down, and said it was believed that the plane had crashed due to a malfunction.

This is a developing story. More information will be added as it becomes available.