A major explosive factory deep inside Russia which supplies Vladimir Putin’s army was attacked, says Ukraine.
The plant is in the Tambov region hundreds of miles from the border with Ukraine.
“The enterprise is one of the main suppliers of explosive materials for the army of the Russian Federation,” said Andriy Kovalenko, the head of Ukraine’s Centre for Countering Disinformation.
“With the start of the full-scale war in Ukraine, production at the plant increased significantly.”
Earlier in January, Ukraine targeted military factories in Rostov and Leningrad.
Ukraine and Russia have regularly attacked military production facilities deep inside each other’s territory in the course of their war which has seen an exponential rise in the use of drones.
Ukraine has struck targets more than 900 miles inside Russia.
Both Kyiv and Moscow have come under attacks from drones.
Military experts say drones may now be having more impact on the battlefield than soldiers.
Ukraine downed 34 out of 55 drones launched by Russia in an overnight attack, the Ukrainian air force said on Thursday, with a further 18 failing to reach their targets, something which usually indicates they were jammed by electronic warfare.
Drones were reportedly downed in 11 regions across Ukraine.
Falling drone debris damaged energy infrastructure in the central region of Poltava, leaving more than 300 users without power, local authorities said.
Over the past few months, Russia has sent near-nightly waves of dozens of long-range strike drones into Ukraine, forcing Kyiv to expend valuable resources to down them.
Ukraine recently targeted an oil depot in the city of Engels which supplies the air base for Russia’s strategic nuclear bomber planes.
The attack led to a state of emergency being declared and the fire took five days to put out, according to civic chiefs.
Sir Keir Starmer visited Kyiv on Thursday, vowing that Britain would stand by Ukraine for the long term.
The Prime Minister said the UK would “never let up” on support for Ukraine as he made his first visit to Kyiv since taking office.
Donald Trump is due to return to the White House for a second term as president on January 20, having argued that he can swiftly end the war in Ukraine.
However, Foreign Secretary David Lammy has said that there is no evidence that Putin wants a peace deal.