Ukraine used US-supplied ATACMS missiles to strike an arsenal in Russia's Bryansk region on Tuesday, Ukrainian and US official sources confirmed on Tuesday. 

Moscow said earlier that Ukraine had used ATACMS missiles to strike Russian territory for the first time, in an attack regarded by Russia as an escalation on the war's 1,000th day.

The move comes just days after President Joe Biden's administration allowed Ukraine to use the weapons to strike deep into Russia, a significant reversal of Washington's policy in the Ukraine-Russia conflict.