Iran's president tweeted about a time the US accidentally shot down an Iranian passenger jet two days before Iran may have inadvertently shot down a Ukrainian flight.

Multiple reports on Thursday said evidence indicates Iran accidentally shot down Ukrainian Airlines Flight 752 shortly after it launched a missile attack on US and coalition forces in Iraq.

The US and Iran have since moved away from a wider conflict, but tensions are still high.

Prior to the plane crash, as Iran and the US traded threats, Iranian President Hassan Rouhani tweeted about the 290 people killed when a US warship accidentally shot down Iran Flight 655 in 1988.

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Evidence is mounting that Iran accidentally shot down Ukrainian Airlines Flight 752 with an antiaircraft missile on Wednesday, according to multiple reports, just two days after Iranian President Hassan Rouhani reminded the world of the time the US inadvertently shot down an Iranian passenger jet.

Iran Air Flight 655 was shot down by a US warship, the USS Vincennes, in 1988. All 290 passengers were killed. The incident occurred as American and Iranian ships skirmished in the Persian Gulf, and the US government claimed it was an accident. The Iranian government, however, viewed the tragedy as purposeful. It's among the many incidents that have fueled ongoing resentment between Iran and the US.

On January 6, Rouhani tweeted: "Those who refer to the number 52 should also remember the number 290. #IR655 Never threaten the Iranian nation."

The 52 in Rouhani's tweet refers to the number of hostages held for 444 days in the 1979 Iranian hostage crisis during the Islamic Revolution.

Rouhani, whose hashtag #IR655 referred to Iran Flight 655, was seemingly responding to President Donald Trump's recent threat to hit 52 Iranian targets. The number 52 was specifically chosen in reference to the 1979 hostage crisis at the US Embassy in Tehran. At the time, Iranian students took dozens of Americans hostage. Initially, 66 Americans were taken hostage, but that number dwindled to 52 by July 1980 as some hostages were released for various reasons.

Trump's threats came as Iran vowed to avenge the US president's order to kill Maj. Gen. Qassem Soleimani, the country's top general. Iran eventually did strike back, launching over a dozen missiles at US and coalition forces early on Wednesday. No US casualties were reported, and Iran and the US have since moved toward deescalation.

Around the same time as Iran's missile attack, Ukrainian Airlines Flight 752 crashed outside the Iranian capital of Tehran, killing all 176 people on board.

Multiple reports on Thursday suggested the flight was hit by a Soviet-built Tor (SA-15) surface-to-air missile system operated by the Iranian military. So far, Iranian officials appear to be rejecting these reports, suggesting it's "scientifically impossible" the Ukrainian flight was shot down by a surface-to-air missile given the elevation it was flying at, even though the jetliner's 8,000-foot altitude was well within the 20,000-feet effective range of the Tor M1.

Prior to the reports suggesting Iranian accidentally shot down the Ukrainian flight, Rouhani in a tweet said, "The crash of a Ukrainian passenger plane in Tehran that killed numerous Iranians, including a group of students, as well as other nationalities, deeply saddens all Iranians."

When asked about the crash by reporters at the White House on Thursday, Trump said, "It's a tragic thing when I see that. It's a tragic thing. But somebody could've made a mistake on the other side."

"It was flying in a pretty rough neighborhood, and somebody...could've made a mistake," Trump told reporters.