On Saturday Iran's foreign ministry summoned Ukraine's chargé d'affaires in Tehran to protest what it called a hostile and criminal attack on an Iranian ship in the Caspian Sea. Reported as a single incident, it reads like a new quarrel between two countries with no particular history.

They have six years of quarrel behind them, and it begins with a passenger plane.

January 2020

On 3 January 2020 an American drone killed Qassem Soleimani in Baghdad. Five days later Iran fired ballistic missiles at US bases in Iraq. Within hours of that barrage, in the small hours of 8 January, Ukraine International Airlines Flight PS752 took off from Tehran for Kyiv and was hit by two Iranian surface-to-air missiles minutes into its climb.

All 176 people on board were killed. The Revolutionary Guard had mistaken the airliner for an American missile coming back at them.

The dead were not mainly Ukrainian, and it matters to say so. Aboard were 55 Canadian citizens and 30 permanent residents, with 53 more passengers bound for Canada, many of them Iranian students returning to universities there. There were Iranians, Swedes, Afghans and Britons. The nine crew were Ukrainian.

For three days Iran called it an accident. Then it admitted its forces had fired.

The case that never closed

Six years on, the file is still open in three international bodies at once. Canada, the United Kingdom, Sweden and Ukraine have pressed jointly for accountability at the International Civil Aviation Organization, the International Court of Justice and the International Criminal Court.

The families of six of the dead won a default judgment against Iran worth $107 million in an Ontario court, Iran having declined to defend itself. Collecting it proved another matter. In May 2024 the Supreme Court of Canada declined to hear their appeal to seize Iranian property and bank accounts in Canada, after a lower court found those assets shielded by diplomatic immunity. Iran has been accused by the families of stalling on reparations. An Iranian prosecutor has said 10 people were indicted at home over the downing.

A separate strand of litigation went the other way, against the airline rather than the state. Ontario courts found Ukraine International Airlines negligent for flying at all into an escalating military crisis, and the province's appeal court upheld compensation above the standard liability cap of US$180,000 a passenger.

That is the relationship Iran and Ukraine were carrying when Russia invaded.

The drones

From the autumn of 2022, Russia began attacking Ukrainian cities with Shahed-136 drones of Iranian design. Ukraine's response was diplomatic before it was technical.

In September 2022 Kyiv stripped Iran's ambassador of his accreditation and cut the size of the Iranian embassy. "Today the Russian army used Iranian drones for its strikes," Zelenskyy said. "The world will know about every instance of collaboration with evil, and it will have corresponding consequences." Ukraine's foreign ministry called arming Russia an unfriendly act that dealt a serious blow to relations.

Kyiv's foreign minister went further and proposed cutting ties altogether. That step had still not been taken by 2023, and the relationship appears to have been downgraded rather than ended. The proof is in the summons itself: there is a Ukrainian chargé d'affaires in Tehran for Iran to call in.

One detail is worth setting down plainly. The ambassador Ukraine expelled in 2022 was named Manouchehr Moradi. The official who summoned Ukraine's envoy on Saturday, according to Anadolu Ajansı, is Manouchehr Moradi, assistant foreign minister and director general for Eurasia. TurkishPress could not confirm they are the same man, and Iran's foreign ministry publishes no accessible biography that would settle it.

What four years of Shaheds taught Kyiv

Being bombed by a weapon teaches you the weapon. Ukraine has spent four years working out how to bring down cheap drones arriving in numbers, and it is now among the most experienced countries in the world at it.

That knowledge turned out to be exportable at the exact moment the United States and Iran went back to war.

On 5 March Washington asked Kyiv for help defending American bases against Iranian drones. Ukraine agreed the same day and sent a team the next, to a US base in Jordan. By 20 March, Zelenskyy said 228 Ukrainian specialists were working in five countries under Iranian fire: the United Arab Emirates, Saudi Arabia, Qatar, Kuwait and Jordan. Local crews handled the ballistic missiles. The Ukrainians took the Shaheds.

He said 11 countries had asked, and that Ukraine wanted money and technology in return. Those figures are from March, and TurkishPress could not confirm how many Ukrainian personnel remain in the region now.

The answer from Tehran

Ebrahim Azizi, who chairs the Iranian parliament's national security and foreign policy committee, wrote that Ukraine could become a "legitimate target." His reasoning: "By providing support to the Israeli regime with drones, the collapsing Ukraine has in fact become involved in the war." He offered no evidence, and a committee chairman does not speak for the state.

Then came Saturday. Zelenskyy announced long-range strikes on vessels carrying military cargo for Iran in the Caspian, and a warship. Iran said the ship was a commercial vessel and that a sailor was killed. Neither account has been verified by anyone outside the two governments.

Iran's foreign minister, Abbas Araghchi, has since said the attack will not go unanswered, and told both the European Union's Kaja Kallas and Russia's Sergey Lavrov as much.

Where that leaves it

Iran maintains it has never intervened in the war between Russia and Ukraine. Ukraine's four-year experience of Iranian-designed drones over its apartment blocks is the counter-argument, and it is the one Kyiv makes.

Neither state has declared anything against the other. There is no war between them and no formal break in relations, only a downgrade that left each capital holding the other's business at arm's length. The record instead runs: a plane, a fleet of drones, a set of judgments nobody can enforce, 228 specialists in five Gulf countries, and a ship destroyed in a sea that Iran borders and Ukraine can reach.

Six years of that, and Tehran can still pick up the phone and summon a Ukrainian diplomat to come in and be shouted at.