Ukraine has proposed that it and Russia halt attacks on civilian targets in the Black Sea, according to a source familiar with the matter, as escalating strikes on vessels and port infrastructure intensify concerns over agricultural exports and global food supplies.

The offer was transmitted by Kyiv through a third party, and Ukraine was awaiting a response from Moscow, the source said. The Kremlin and Russia’s foreign ministry did not immediately comment on the reported initiative.

Before the offer was reported, Russian Deputy Foreign Minister Alexander Grushko said Moscow had not received a formal proposal for a Black Sea ceasefire. He acknowledged that ideas for moratoriums and truces had been raised through different channels but said no official proposal had reached Russia.

The development follows mounting disruption to maritime trade in the region. Russia and Ukraine, both major participants in global agricultural markets, have accused each other of increasing attacks on vessels involved in export operations.

In Ukraine, many shipowners stopped calling at ports in the southern Odesa region in late July after Russian strikes on dozens of ships. Odesa is a major hub for Ukrainian grain exports, and the reduction in vessel calls forced Kyiv to rely more heavily on alternative shipment routes.

Russia also faced interruptions at Novorossiysk, where operations at all three terminals of the Black Sea port were suspended on Wednesday and Thursday following a Ukrainian attack. The disruption is expected to require a further reduction in Russian grain exports.

Ukrainian grain exports have fallen 76% year on year so far in August amid what the source described as a de facto blockade of Black Sea ports. Ukraine says alternative routes by rail and through the Danube have very limited capacity. The country’s agricultural sector has warned that a prolonged disruption would have severe consequences for the economy.

Following Russia’s invasion in 2022, the United Nations and Turkey brokered an agreement that allowed Ukrainian grain exports to continue through the Black Sea. Russia declined to extend that arrangement in 2023. Ukraine subsequently established another maritime corridor, which remained operational until the latest escalation.

Turkey conveyed its concerns to both sides on Sunday and urged Russia and Ukraine to declare a moratorium on Black Sea attacks. The report of Kyiv’s proposal also affected commodity trading, with Euronext wheat retreating from a two-week high during volatile trading on Thursday.