MOSCOW: Russian President Vladimir Putin on Tuesday lowered the threshold for a nuclear strike in response to a broader range of conventional attacks, as Ukraine used US ATACMS missiles to strike Russian territory, taking advantage of newly granted permission from the outgoing Biden administration on the war’s 1,000th day.

Russia said its forces shot down five of six of the missiles, which were fired at a military facility in the Bryansk region. Debris of one hit the facility, starting a fire that was swiftly put out and caused no casualties or damage, it said. Ukraine said it had struck a Russian arms depot around 110 km inside Russia in an attack that caused secondary explosions. US President Joe Biden gave approval just this week for Ukraine to use the ATACMS, the longest-range missiles Washington has supplied, for such attacks inside Russia. Moscow has described their potential use as an escalation that would make Washington a direct combatant in the war and prompt its retaliation.

The attack took place as Ukraine marked 1,000 days of war, with weary troops at the front, Kyiv besieged by airstrikes, a fifth of Ukrainian territory in Moscow’s hands and doubts about the future of Western support as Donald Trump heads back to the White House. Russia had been warning the West for months that if Washington allowed Ukraine to fire US, British and French missiles deep into Russia, Moscow would consider those NATO members to be directly involved in the war in Ukraine.

The updated Russian nuclear doctrine, establishing a framework for conditions under which Putin could order a strike from the world’s biggest nuclear arsenal, was approved by him on Tuesday, according to a published decree. Analysts said the biggest change was that Russia could consider a nuclear strike in response to a conventional attack on Russia or its ally Belarus that “created a critical threat to their sovereignty and (or) their territorial integrity”. Washington said the update to the nuclear doctrine was no surprise

and cited “more of the same irresponsible rhetoric from Russia”. The US National Security Council said it had not seen any reason to adjust the US nuclear posture. The previous doctrine, contained in a 2020 decree, said Russia may use nuclear weapons in case of a nuclear attack by an enemy or a conventional attack that threatened the existence of the state. The doctrine said any attack by a non-nuclear power supported by a nuclear power would be considered a joint attack, and that any attack by one member of a military bloc would be considered an attack by the entire alliance, it said.

“We will be taking this as a qualitatively new phase of the Western war against Russia and we will react accordingly,” Putin’s foreign minister, Sergei Lavrov, said in English, adding that US personnel and data must have been used in the ATACMS attack on Russia. Lavrov said Russia would do everything to avoid nuclear war, and pointed out that it was the US which used nuclear weapons against the Japanese cities of Hiroshima and Nagasaki in 1945.

Russia also included a broader definition of the data that could be used to indicate Russia was under mass attack from aircraft, cruise missiles and unpiloted aircraft. The war is entering what some Russian and Western officials say could be its final and most dangerous phase as Moscow’s forces advance at their fastest pace since the early weeks of the conflict and the West ponders how the war will end.

The Kremlin said Russia considered nuclear weapons a means of deterrence and that the updated text was intended to make clear to potential enemies the inevitability of retaliation should they attack Russia. “Now the danger of a direct armed clash between nuclear powers cannot be underestimated, what is happening has no analogues in the past, we are moving through unexplored military and political territory,” said Sergei Ryabkov, Russia’s deputy foreign minister overseeing arms control and US relations.

Asked whether publication of the decree was linked to Washington’s decision on allowing Ukraine to fire US missiles deep into Russia, Kremlin spokesman Dmitry Peskov said the doctrine had been published in a “timely manner”. “Nuclear deterrence is aimed at ensuring that a potential adversary understands the inevitability of retaliation in the event of aggression against the Russian Federation and/or its allies,” Peskov said.

The warring sides have both been escalating in recent weeks in an attempt to secure a stronger position at any negotiations. Ukrainian President Volodymyr Zelenskiy says Kyiv must do everything for the war to end diplomatically next year. “At this stage of the war, it is being decided who will prevail. Whether us over the enemy, or the enemy over us Ukrainians... and Europeans. And everyone in the world who wants to live freely and not be subject to a dictator,” he said in an address to parliament on Tuesday marking 1,000 days of war.

Thousands of Ukrainian citizens have died, over six million live as refugees abroad and the population has fallen by a quarter since Putin ordered the invasion by land, sea and air that began Europe’s biggest conflict since World War Two. Military losses have been huge, although casualty figures remain closely guarded secrets. Public Western estimates based on intelligence reports say hundreds of thousands have been wounded or killed on each side.

“In the frozen trenches of the Donetsk region and in the burning steppes of the Kherson region, under shells, hail, and anti-aircraft guns, we are fighting for the right to live,” Ukraine’s top commander Oleksandr Syrkyi wrote on Telegram. Tragedy has touched families in every corner of Ukraine, where military funerals are commonplace in cities and far-flung villages, and people are exhausted by sleepless nights of air raid sirens and anguish.

In a move decried in the West as an escalation, Russia has now deployed 11,000 North Korean troops, some of whom Kyiv says have clashed with Ukrainian forces in Kursk. Zelenskiy said Pyongyang could send 100,000 soldiers. Russia for its part continues to advance village by village in eastern Ukraine, claiming to have captured another settlement on Tuesday. – Reuters