LONDON: Russia's military targeted a civilian cargo ship in the Black Sea with "multiple missiles" last month but they were successfully intercepted by Ukrainian forces, Britain said on Monday citing intelligence.

A vessel in Russia's Black Sea fleet fired the missiles, which included two Kalibr cruise missiles, towards the southern Ukrainian port of Odessa on August 24, according to the UK government.

Declassified intelligence has revealed that the intended target was a Liberian-flagged cargo ship berthed there, the Foreign, Commonwealth and Development Office (FCDO) said.

It added Ukrainian air defences thwarted the attack on the civilian vessel, with neither of the Kalibr missiles hitting their target.

Cargo ship in Black Sea: Russian warship fires shots

"Despite its failure, this is a clear demonstration of Russia's continuing attempts to choke Ukraine's economy," the FCDO said in a statement.

It accused Russian President Vladimir Putin of "disregard for the lives of civilians" and of trying to "weaponise food and innocent trade at the expense of the rest of the world".

The Black Sea has become increasingly contested after Russia in July pulled out of a UN- and Turkey-brokered grain deal, which aimed to ensure safe navigation for civilian ships.

Moscow has since repeatedly attacked Ukraine's port infrastructure, in what Kyiv says is a cynical attempt to damage its exports and undermine global food security.

Referencing the alleged August 24 targeting of the civilian ship while making a statement in parliament about last weekend's G20 summit, British Prime Minister Rishi Sunak said it showed "just how desperate Putin is".

He added Russian attacks on Ukrainian sites had destroyed more than 270,000 tonnes of grain, noting that was "enough to feed a million people for a year".

"Ukraine has the right to export its goods through international waters and they have the moral right to ship grain that is helping feed the world," Sunak said.