The British government on Wednesday announced a fresh round of sanctions targeting Russia over its invasion of Ukraine.

Foreign Secretary James Cleverly said the new sanctions on organisations that Russian President Vladimir Putin's military relied on would "accelerate the economic pressure on Putin -- undermining his war machine to help Ukraine prevail".

The sanctions package, announced as Ukrainian President Volodymyr Zelensky visited the UK, would hit six organisations providing military equipment such as drones.

It would also target eight individuals and one organisation connected to "nefarious financial networks that help maintain wealth and power amongst Kremlin elites", the government said in a statement.

"I am determined, consistent with our laws, that Russia will have no access to the assets we have frozen until it ends, once and for all, its threats to Ukraine's territorial sovereignty and integrity," Cleverly added.

The UK has sanctioned over 1,300 individuals and entities since Putin unleashed his invasion nearly a year ago.