Iran on Jan. 11 admitted that it unintentionally shot down the Ukrainian Boeing 737-800 plane which killed 176 people onboard.

The admission follows skepticism from Western leaders, including U.S. President Donald Trump, Canadian Prime Minister Justin Trudeau and U.K. Prime Minister Boris Johnson, who had expressed doubts about mechanical issues causing a crash.

"Armed Forces' internal investigation has concluded that regrettably missiles fired due to human error caused the horrific crash of the Ukrainian plane & death of 176 innocent people," Iranian President Hassan Rouhani said in a tweet.

The aircraft, which was bound for Ukraine, crashed shortly after takeoff from Tehran. The news came after Iran fired ballistic missiles in Iraq in retaliation to an American airstrike that killed its top military commander.

Iran's Foreign Minister Mohammad Javad Zarif also admitted the incident on Twitter, saying: "human error at time of crisis caused by US adventurism led to disaster."