Russia vowed on Saturday to retaliate after it accused Ukraine of firing US-supplied ATACMS missiles at the border region of Belgorod the previous day.Outgoing US President Joe Biden authorized Kyiv to use the long-range weapons against Russia last year, in a move the Kremlin denounced as a grave escalation of the nearly three-year conflict.“On January 3, an attempt was made from Ukrainian territory to launch a missile strike against the Belgorod region using US-made ATACMS operational-tactical missiles,” the Russian defense ministry said.For the latest updates on the Russia-Ukraine war, visit our dedicated page.“These actions by the Kyiv regime, which is supported by Western curators, will be met with retaliation,” it added, saying all the missiles were shot down.The ministry said earlier that air defenses downed eight ATACMS missiles in total, without saying when or where.Russian President Vladimir Putin threatened last year to strike central Kyiv with a hypersonic ballistic missile