The Ukraine International Airlines plane was hit by two missiles Iran says were fired in error shortly after takeoff, killing 176 people.
The four countries, which all had citizens on board the Ukraine International Airlines flight, accused Tehran of “using weapons against a civil aircraft in flight in breach of its international legal obligations”.
The Boeing 737-800 was shot down shortly after takeoff from Tehran on January 8, 2020, amid rising tensions with the United States following the assassination of Iranian General Qassem Soleimani.
Three days later, Iran admitted that its Revolutionary Guard had fired two missiles at the plane, which was heading to Kyiv, by mistake.
The four countries said they opened “dispute settlement proceedings” with the UN’s International Civil Aviation Organization (ICAO) in Montreal.
The move was “an important step in our commitment to ensuring that the families of the victims impacted by this tragedy get the justice they deserve”, said Canadian Prime Minister Justin Trudeau, who attended a memorial service in Ontario to mark the fourth anniversary of the disaster.
The countries have already filed a case with the International Court of Justice (ICJ) in The Hague, seeking reparations from Iran for the families of the victims.
They said Iran had “failed to conduct an impartial, transparent and fair criminal investigation and prosecution consistent with international law”.
In April last year, an Iranian court issued initial sentences for 10 unnamed people accused of involvement in the incident, including the operator of an air defence system.
Iran has also set compensation of $150,000 for each of the families of the victims and said in 2022 it had begun making the payments.
Tehran has rejected claims that it is not cooperating or being transparent and has accused the four governments of trying to “politicise” the issue.
It has filed its own case with the ICJ, accusing Canada of violating its “international obligations” by allowing people to seek civil damages against Tehran.