Britain on Tuesday said it had sanctioned 12 Russian military commanders implicated in missile strikes on Ukrainian cities as well as Iranian businessmen involved in the production and supply of military drones used in the attacks.
On Monday, Ukraine said Russian missiles, artillery and drones had hammered targets in eastern and southern Ukraine.
Britain said Iranian-manufactured drones had played a central role in attacks on civilians, citing US information showing Iran has become one of Russia’s top military backers, sending hundreds of drones to Russia.
Tehran and Moscow have denied Western accusations that Russia is using Iranian drones to attack targets in Ukraine.
"Russian forces’ calculated attacks on cities and innocent civilians in Ukraine will not go unanswered," British Foreign Secretary James Cleverly said.
"The Iranian regime is increasingly isolated in the face of deafening calls for change from its own people and is striking sordid deals with Putin in a desperate attempt to survive."
Britain said among those sanctioned were Major General Robert Baranov, believed to be the commander of a unit responsible for programming and targeting Russian cruise missiles.