Ukrainian presidential adviser Mykhailo Podolyak has reiterated his call for Ukraine to be allowed to use Western weapons to strike targets on Russian territory, as some of the country's allies appear to be considering such a step.
Lifting restrictions on weapons provided by Western allies to enable Ukraine to target Russia was in line with international law, Podolyak said on a talk show hosted by German public broadcaster ZDF on Thursday evening.
To stop Moscow, which has been waging a war against Ukraine for more than two years, Kiev must also be able to target military facilities in Russia, Podolyak said.
Following lethal shelling of Kharkiv, Ukraine's second largest city in the north-east near the Russian border, Ukrainian President Volodymyr Zelensky had called for Ukraine to be granted permission to use Western weapons against Russian territory.
NATO Secretary General Jens Stoltenberg has also recently backed that demand, urging member states to at least partially lift restrictions for Ukrainian attacks.
According to media reports on Thursday, Washington has quietly authorized Ukraine to use weapons provided by the US on a limited scale against targets on Russian territory.
This applies exclusively to counter-attacks in defence of Kharkiv, Politico and broadcaster CNN reported.
In Europe, leaders don't appear to have agreed on a common stance yet. While French President Emmanuel Macron is in favour of partially lifting restrictions, German Chancellor Olaf Scholz has so far not signalled publicly that he would be open to such a step.
German Defence Minister Boris Pistorius, who was in Ukraine on Thursday, also struck a cautious note. International law allowed for restrictions on the use of weapons provided to Ukraine to be lifted, the minister told ZDF.
However, Pistorius also pointed to bilateral agreements between Ukraine and its Western allies, which involved "details that you don't talk about publicly because you should never talk about what you are prepared to do, what you allow and what you don't allow."
The Kremlin would never consider revealing its cards like that, the German minister added.