KYIV, Ukraine — The Kremlin warned Monday that President Joe Biden’s decision to let Ukraine strike targets inside Russia with U.S.-supplied longer-range missiles adds “fuel to the fire” of the war and would escalate international tensions even higher.

Biden’s shift in policy added an uncertain, new factor to the conflict on the eve of the 1,000-day milestone since Russia began its full-scale invasion in 2022. It also came as a Russian ballistic missile with cluster munitions struck a residential area of Sumy in northern Ukraine, killing 11 people and injuring 84 others. Another missile barrage sparked apartment fires in the southern port of Odesa, killing at least 10 people and injuring 43, Ukraine’s Interior Ministry said.

Washington is easing limits on what Ukraine can strike with its American-made Army Tactical Missile System, or ATACMs, U.S. officials told The Associated Press on Sunday, after months of ruling out such a move over fears of escalating the conflict and bringing about a direct confrontation between Russia and NATO.

The Kremlin was swift in its condemnation. “It is obvious that the outgoing administration in Washington intends to take steps, and they have been talking about this, to continue adding fuel to the fire and provoking further escalation of tensions around this conflict,” spokesman Dmitry Peskov said. Russia’s U.

N. Ambassador Vassily Nebenzia went further at a U.N.

Security Council meeting marking 1,000 days of war, saying Moscow .