^{Soldiers carry a coffin containing the remains of one of the eleven Ukrainian victims of the Ukraine International Airlines flight 752 plane disaster during a memorial ceremony at the Boryspil International Airport, outside Kiev, Ukraine January 19, 2020. Ukrainian Presidential Press Service/Handout via REUTERS}

(Reuters) - Canada, Britain, Sweden and Ukraine are to move to the International Court of Justice in their bid to hold Iran accountable for the downing of an airliner by Iranian forces in 2020 that killed several people, they said on Thursday.

Most of the 176 people killed when Iran shot down the Ukrainian jet near Tehran in January 2020 were citizens from those four countries, which created a coordination group that seeks to hold Iran to account.

Iran says its Revolutionary Guards accidentally shot down the Boeing 737 jet and blamed a misaligned radar and an error by the air defense operator at a time when tensions were high between Tehran and Washington.

The four counties had earlier sought for Iran to submit to arbitration under the rules of the 1971 Montreal Convention, an international treaty which requires states to prevent and punish offences against civil aviation. The deadline for a settlement passed on Thursday.

Iran had also separately filed a complaint against Canada at the United Nation's top court, accusing Canada of violating international obligations by allowing people to seek damages against Tehran. Ottawa said it was analyzing Iran's application and "will take the appropriate next steps as per the International Court of Justice's procedures."

Last year, an Ontario court awarded C$107 million ($81 million), plus interest, to the families of six people who died when the Iranian Revolutionary Guards downed the Ukraine International Airlines plane.

At the time, Iran was on edge about possible attacks after it fired missiles at Iraqi bases housing U.S. forces in retaliation for the killing days before of its most powerful military commander, Qassem Soleimani, in a U.S. missile strike.

Canada cut diplomatic ties with Iran in 2012 and listed the country as a supporter of extremism. It also recently imposed sanctions on Iran over alleged human rights abuses and the killing of Mahsa Amini, a woman who died in the custody of Iran's morality police that enforced strict dress codes.