Russian President Vladimir Putin warned that Russia could supply weapons to other countries that would use them against Western nations, if the allies continue to supply Ukraine with weapons. 

"If someone thinks it is possible to supply such weapons to a war zone to attack our territory and create problems for us, why don’t we have the right to supply our weapons," Putin stated during a press conference in St Petersburg. "That is, the response can be asymmetric. We will think about it."

Russia is allied with various countries that skirmishing with the West such as Houthi rebels in Yemen that have been targeting Western ship traversing the Red Sea, a major global trade route. Likewise, Moscow and Tehran have moved closer together and Iran fired missiles directly at Israel for the first time in April.

Putin's comments followed confirmation from a US senator and a Western official that Ukraine had recently used US weapons to strike targets inside Russia.

"Delivering arms to a warzone is always bad. Even more so if those who are delivering are not just delivering weapons but also controlling them. This is a very serious and very dangerous step," Putin said.

A Russian refinery was hit the same day suffering major damage that observers say could have been hit with a US-made HIMARS missile. Ukraine has been targeting Russian refineries using new home made long distance drones since January, but those drones are not powerful enough to do more than superficial damage that has been quickly repaired for the most part. Until now, Ukraine has refrained from using the more powerful and accurate US-made missiles against targets on Russian soil.

Putin repeated his claim that Russia "did not start the war against Ukraine," instead blaming a pro-Western revolution in 2014.

"Everyone thinks that Russia started the war in Ukraine. I would like to emphasize that nobody in the West, in Europe, wants to remember how this tragedy started," Putin said.

The Biden administration has been reluctant to approve the use of Western-made missiles against targets inside Russia for fears of escalating tensions and provoking a response by Russia against a western country – fears that Putin was playing on with his comments on June 5.

However, after Russia intensified its assault on Kharkiv and Ukraine’s regions along the Russian border in the last month, US President Joe Biden has been persuaded to relax the restrictions as the Armed Forces of Ukraine (AFU) begins to lose territory. Russia has been launching drone and missile attacks from inside Russia just across the border with impunity thanks to the ban on using US-made missiles to hit targets in Russia.

Russian troops have captured 752 square kms of territory since the start of this year, according to Institute for the Study of War (ISW), after the frontline had not moved more than a few kilometres for most of last year.

Republican Senator Mike Rounds of South Dakota, a member of the Senate Armed Services Committee, confirmed the strikes involving US weapons but did not disclose the source of his information, The Guardian reported. Biden's new directive permits the use of US-supplied weapons to strike Russian forces inside Russia attacking or preparing to attack but limits the permission to areas “near Kharkiv.”

Ukraine has been given permission to use the High Mobility Artillery Rocket System (HIMARS) missiles that have a limited range, but the ban on using the more powerful and longer-range Army Tactical Missile Systems (ATACMS) remains in place.

Berlin has also recently authorised Ukraine to target certain sites on Russian soil with German-supplied long-range weapons, a move Putin described as a "dangerous step" that could damage relations between Berlin and Moscow.

Ukrainian officials continue to lobby the White House and other allies to relax the ban further in the hopes of using these missiles to hit high value targets like oil refineries that are much deeper in Russian territory. Ukraine’s attacks on Russia’s oil refineries have reduced the output of oil products by an estimated 14% this year and are affecting Russia’s oil product exports.

Ukrainian forces struck a Russian S-300/400 air defence battery in the Belgorod region, according to ISW, likely using a HIMARS on June 2. The air defence system was situated approximately 60km from the frontline in the northern Kharkiv region and more than 80km from Kharkiv city, within the range of HIMARS, the institute reported.