British intelligence has issued a warning to insurers that Russia is poised to use sea mines to target civilian shipping in the Black Sea.

It comes as Russian attacks have already destroyed enough grain to feed more than one million people for a year. On Thursday, the UK released a declassified report warning that Russia would lay blame on Ukraine for any attacks.

The UK has previously warned that the Russian military had attempted a missile strike against a cargo ship in the Black Sea.

It says Russia is seeking to target civilian shipping travelling through Ukraine’s humanitarian corridor in order to deter the export of Ukrainian grain in a bid to continue it’s attempts to pressure the Ukrainian economy.

"Russia’s pernicious targeting of civilian shipping in the Black Sea demonstrates President Putin’s total disregard for civilian lives and the needs of the world’s most vulnerable," Foreign Secretary James Cleverly said. "The world is watching – and we see right through Russia’s cynical attempts to lay blame on Ukraine for their attacks.

"We and our allies stand united against Mr Putin and his attempts to harm Ukraine and thus harm the rest of the world."

The UK has increased support to help the world's poorest to receive grain following Russia’s decision to withdraw from the Black Sea Grain Initiative in July.

The pact had facilitated the safe Black Sea export of grain from Ukraine to the world's poorest countries. "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," the UK government said.