Four countries have called on Iran to submit to arbitration and be held accountable for the downing of Ukrainian Airlines Flight PS752.
The Boeing aircraft was hit by two missiles after leaving Tehran for Kyiv on 8 January 2020, killing all 176 people on board.
Canada, Ukraine, Sweden, and the UK have urged Tehran to settle a dispute, nearly three years after the incident.
The four countries say they are taking “concrete action” against Iran under the 1971 Montreal Convention, which regulates civil aviation offences.
They have accused Iran’s Islamic Revolutionary Guard Corps of having “unlawfully and intentionally” downed the plane.
If Iran does not agree to arbitration within six months, the case could be sent to the UN’s International Court of Justice in the Hague.
Iranian armed forces only admitted three days later that they had shot down the plane “by mistake” amid heightened tensions with the United States.