Responding to reports that an Iranian missile downed a Ukrainian plane with 176 people on board, presidential candidate Pete Buttigieg claimed the attack was the result of "unwanted military tit for tat."

"Innocent civilians are now dead because they were caught in the middle of an unnecessary and unwanted military tit for tat," the former South Bend mayor tweeted.

A British diplomat told the Washington Examiner that an Iranian anti-aircraft missile system inadvertently shot down the Boeing 737-800 after taking off from Tehran's Imam Khomeini International Airport.

The passengers killed included 82 Iranians, 63 Canadians, 11 Ukrainians, 10 Swedes, four Afghans, three Germans, and three British nationals.

At a press conference Thursday, President Trump said the jet was flying through a "rough neighborhood" and that he had "suspicions" about the reason why the plane crashed and videos published to social media show the jet on fire as it fell from the sky.

Buttigieg has become a late-favorite in the race for the 2020 Democratic nomination, passing Massachusetts Sen. Elizabeth Warren in New Hampshire as the favorite to win the state with 20% support in a Thursday Monmouth poll.