Ukraine used US-supplied ATACMS missiles to target Russian territory on Tuesday, marking the war's 1,000th day, Reuters reported. 

This strike followed newly granted permission from the outgoing Biden administration.

Russia claimed to have intercepted five of the six missiles fired at a military facility in its Bryansk region. It reported that debris from one missile caused a fire at the site but resulted in no casualties or damage. In contrast, Ukraine said the attack hit a Russian arms depot 110 km inside Russian territory, causing secondary explosions.

While Ukraine’s military did not publicly confirm the use of ATACMS, a Ukrainian government source and a US official verified the deployment of the long-range missiles. A US official, speaking anonymously, stated that Russia intercepted two of the eight missiles launched, with the strike targeting an ammunition depot.

President Joe Biden recently authorised Ukraine to use ATACMS, the longest-range missiles provided by Washington. Moscow has warned that deploying these missiles would escalate the conflict, positioning the US as a direct participant and prompting potential retaliation.

This development coincided with Ukraine marking 1,000 days of conflict, during which a fifth of its territory remains under Russian control. Concerns about continued Western support loom as Donald Trump prepares to assume the presidency.

The ATACMS missiles, with a range of up to 300 km, grant Ukraine the ability to strike deeper into Russian territory, though still far short of the ranges of Russia's Kinzhal hypersonic missiles. Military analysts say such strikes could strengthen Ukraine's bargaining position but are unlikely to shift the war's trajectory significantly.

In response, Moscow reiterated that using such weapons requires direct US involvement, effectively implicating Washington in the conflict. On the same day, President Vladimir Putin signed a nuclear doctrine lowering the threshold for Russia’s use of atomic weapons, framing it as a warning to the US.