US officials say President Biden has given the green light for Ukraine to use long range missiles supplied by Washington to strike deep inside Russia. Washington had previously refused to allow such strikes with US-made ATACMS missiles because it feared they would escalate the war.

Ukraine used U.S. ATACMS missiles to strike Russian territory on Tuesday, taking advantage of newly granted permission from the outgoing administration of U.S. President Joe Biden on the war's 1,000th day.

The Biden administration has allowed Ukraine to use Army Tactical Missiles Systems, a long-range missile system that often carries cluster bombs.