Two missiles hit the city of Odesa in the early hours of Saturday morning, Ukraine's military was quoted as saying by BBC.

Under the terms of Friday's deal, Russia agreed not to target ports while grain shipments are in transit, the British media reported.

EU foreign affairs chief Josep Borrell condemned Russia's move and tweeted: "EU strongly condemns Russian missile strike on Odesa’s seaport. Striking a target crucial for grain export a day after the signature of Istanbul agreements is particularly reprehensible & again demonstrates Russia’s total disregard for international law & commitments."

Russian and Ukrainian Ministers signed the Black Sea Grain Initiative, facing each other at opposite ends of the table, while the Secretary-General and Turkish President Recep Tayyip ErdoÄŸan sat in the centre.

Ukraine is among the world’s leading grain exporters, supplying more than 45 million tonnes annually to the global market, according to the UN Food and Agriculture Organization (FAO). 

The Russian invasion, which began on 24 February, has sparked record food and fuel prices, as well as supply chain issues, with mountains of grain stocks stuck in silos.