For the first time since Russia opened its campaign against Ukrainian ports following its withdrawal from a United Nations-brokered grain export deal last week, it has hit infrastructure on the Danube.

According to Ukrainian and Russian sources, explosions occurred early on Monday at Reni and Izmail — Ukrainian towns where the river forms the border between Ukraine and Romania.

A Ukrainian official confirmed on his Telegram channel that port infrastructure by the Danube was the target and that the Izmail prosecutor’s office has started investigations after at least four grain hangars, oil and fuel storage tanks were damaged and destroyed in the city.

At least four people suffered mild to medium injuries.

According to Ukrainian information, the attacks were not carried out with the type of long-range missiles attacking Odesa and Chernomorsk since 18 July but rather with Iranian-made “Shahed-136” drones.

Reni is situated by Cahul lake, a few miles inland on the Danube, west of Izmail. AIS data on MarineTraffic shows vessel traffic on the river has not stopped after the attack.

According to Russian bloggers, the attacks may not only have been intended to disrupt grain flows but also the supply of oil stored in the region to supply Ukrainian refineries.

The Danube is the last waterborne way to export grain out of Ukraine since 17 July, when Russia quit the UN-brokered Black Sea Grain Initiative.

In a video posted on Youtube by Georgian newspaper Batumelebi, a seafarer recorded the sound of gunfire. The camera shakes as a blast is heard.

The newspaper said that six Georgian seafarers are on the Greek-owned, Maltese-flag ship at the port and are seeking a way out.

Following its exit, Russia has been hammering the ports of Odesa and Chernomorsk with missiles and drones.

The Danube region had been spared, possibly thanks to its proximity to Nato member Romania. On the other hand, the attack on Reni or elsewhere on the Danube seems to be far less intense than Russia’s raids against Ukraine’s big seaports to the north.

The attacks on Monday have been part of tit-for-tat warfare that has intensified since 17 July, with Russia hitting Odesa and Ukraine raining down drones and Western-made missiles on the Russian-annexed Crimea peninsula.

Both Ukraine and Russia have threatened to attack commercial vessels approaching each others’ ports in the Black Sea. The Danube has been the only part of the region so far, where ship traffic has not been affected by the blockade.

Damaged port facilities and a Maersk container box can be seen along the river Danube. Photo: Sergey Bratchuk via Telegram

The attack drew condemnation from Romanian President Iohannis Klaus, for bringing the war to his country’s doorstep.

“I strongly condemn the recent Russian attacks against the Ukrainian civilian infrastructure on Danube, very close to Romania,” he wrote on Twitter. “This recent escalation poses serious risks to the security in the Black Sea. It also affects further [Ukraine] grain transit and thus the global food security.”

Eric Priante Martin contributed to this story.