KYIV, July 12 (AFP) - Russian and Ukrainian officials were to hold talks in Istanbul on Wednesday (Jul 13) over stalled grain deliveries that have pushed global food prices skywards, while Kyiv said it had destroyed a Russian arms depot as the war rages on.

Ukraine is one of the world's biggest exporters of wheat and other grain, but shipments have been blocked by both Russian warships and mines that Kyiv has laid across the Black Sea.

Turkey, which has spearheaded efforts to resume the essential grain trade, will host the talks, which will also be attended by a UN delegation.

On the ground, Kyiv said it had launched artillery that wrecked a Russian arms depot and also carried out a "special operation" to free military captives in the Moscow-controlled Kherson region.

Ukrainian military officials said the strikes on Tuesday had destroyed artillery, armoured vehicles "and a warehouse with ammunition" in the Russian-occupied town of Nova Kakhovka.

"The occupiers have already felt very well what modern artillery is and they will not have a safe rear anywhere on our land," President Volodymyr Zelenskyy said in his evening address.

Russian-backed authorities accused Ukraine of damaging civilian infrastructure and killing at least seven people.

"Warehouses were hit, as were shops, a pharmacy, petrol stations and even a church," the head of the city's Moscow-backed administration, Vladimir Leontiev, said on social media.

Ukrainian military intelligence also said its forces had freed five captives in the "special operation" in Kherson, including a military serviceman and former police officer, without specifying when.