The UK government said it is slapping further sanctions on Russia's main airlines by barring them from selling landing slots they are already banned from using

"State-owned Aeroflot, Russia's largest airline, Ural Airlines and Rossiya Airlines will now be unable to sell their unused, lucrative landing slots at UK airports," the foreign ministry said in a statement.

The move will prevent Russia "from cashing in on an estimated £50 million (59 million euros, $62 million)", it added.

The UK has already banned Russian aircraft and vessels, and sanctioned more than 1,000 Russian individuals and 100 entities, since President Vladimir Putin ordered the invasion of Ukraine in late February.

"As long as Putin continues his barbarous assault on Ukraine, we will continue to target the Russian economy," Foreign Secretary Liz Truss said.

International sanctions against Moscow over its invasion of Ukraine mean that Russia is "heading for the deepest recession since the collapse of the Soviet Union", the statement said.