Western media reports say Ukrainian forces have fired British-supplied long-range Storm Shadow cruise missiles into Russian territory for the first time.

US media outlet Bloomberg on Wednesday quoted a Western official as saying Britain approved the use of the missiles in response to Russia deploying North Korean troops in its war against Ukraine.

Britain's Telegraph newspaper reported that fragments of a Storm Shadow missile were found in a village in Russia's western region of Kursk.

The governor of Kursk posted on social media that two Ukrainian missiles were intercepted on Wednesday afternoon, but did not mention the type of missile.

Storm Shadows have a range of more than 250 kilometers.

Britain is said to have sought approval from the administration of US President Joe Biden for the missiles to be fired into Russia.

British Defence Secretary John Healey said in Parliament on Wednesday that he cannot disclose operational details, but "Ukraine's action on the battlefield speaks for itself."

Russia's defense ministry announced on Tuesday that US-made ATACMS missiles were fired into the Bryansk region in western Russia.

Russian Foreign Minister Sergey Lavrov said President Vladimir Putin had warned Russia's position would change if the use of long-range missiles were approved.