According to BBC reports, it would be acceptable for Ukrainian forces to use Western weapons to attack military targets on Russian soil, a UK defence minister has said.
James Heappey said strikes to disrupt supply lines were an “entirely legitimate” part of war.
Russia’s foreign minister Sergei Lavrov has accused Nato of engaging in a proxy war and said weapons delivered by the West to Ukraine would be fair targets.
The UK announced it will give Ukraine a small number of anti-aircraft vehicles.
Western countries have donated hundreds of millions of pounds of military aid to Ukraine since Russia launched its invasion back in February and Nato and European Union officials are meeting in Germany to discuss further military assistance.
It comes as Russia has focused its forces on the eastern Donbas region of Ukraine, with the UK’s Ministry of Defence reporting the city of Kreminna, in Luhansk, has fallen.
Russia has accused Ukraine of attacking targets within its territory, including an oil depot in Belgorod, but Ukrainian forces have not confirmed any strikes.
Mr Heappey was asked on BBC Radio 4’s Today programme about reports that Ukraine had targeted a fuel depot on Russian territory.
The armed forces minister said: “The question is, is it acceptable for our weapons to be used against legitimate Russian military targets by the Ukrainians?
“Firstly, it’s Ukrainians that take the targeting decision, not the people who manufacture or export the kit in the first place. And secondly, it is entirely legitimate to go after targets in the depth of your opponents to disrupt their logistics and supply lines.”
He added that it was also a “perfectly legitimate” part of war for Russian forces to be striking targets in western Ukraine to disrupt Ukrainian supply lines as long as they avoided targeting civilians – “which unfortunately they have no taken much regard for so far”.