Russia has announced it is suspending its involvement in the internationally-brokered deal that allows Ukraine to export grain from its Black Sea ports.
It comes after Russia accused Ukraine of a "massive" drone attack on the Black Sea Fleet in Sevastopol, Crimea.
Ukraine has not admitted the attack and President Volodymyr Zelensky called the Russian move "rather predictable".
Without providing evidence, Russia also accused British troops of being involved in Saturday’s attack.
It also accused the UK of blowing up gas pipelines last month.
In its response, the UK Ministry of Defence (MoD) said Russia was "peddling false claims of an epic scale".