Russia may use sea mines to target civilian ships in the Black Sea, the Foreign, Commonwealth and Development Office (FCDO) has said.
Latest intelligence shows Russian attacks have already destroyed enough grain to feed more than one million people for a year.
And now the UK assesses Russia is "seeking to target civilian shipping travelling through Ukraine's 'humanitarian corridor' in order to deter the export of Ukrainian grain", including by laying sea mines in the approach to Ukrainian ports.
Intelligence also suggests that Russia would lay blame on Ukraine for any attacks.
This would continue Russia's attempts to pressure the Ukrainian economy," the FCDO said in a statement.
"Russia almost certainly wants to avoid openly sinking civilian ships, instead falsely laying blame on Ukraine for any attacks against civilian vessels in the Black Sea.
"By releasing our assessment of this intelligence, the UK seeks to expose Russia's tactics to deter any such incident from occurring.
Foreign Secretary James Cleverly said "Russia's pernicious targeting of civilian shipping" in the Black Sea demonstrated Vladimir Putin's "total disregard for civilian lives and the needs of the world’s most vulnerable".
"The world is watching – and we see right through Russia's cynical attempts to lay blame on Ukraine for their attacks," he said.
