Russia may escalate its campaign to destroy Ukrainian food exports by targeting civilian shipping in the Black Sea, British Foreign Secretary James Cleverley has said.

"The UK believes that Russia may escalate its campaign to destroy Ukraine's food exports by targeting civilian ships in the Black Sea. We will highlight this unconscionable behaviour at the UNSC. Russia should stop holding global food supplies hostage and return to the deal [the Black Sea Grain Initiative]," the secretary wrote on Twitter.