His powers Vladimir Putin considered a number of scenarios involving the use of tactical nuclear weapons at an early stage of conflict with a great world power. That’s according to leaked Russian military files looking at an invasion by China, as fears of a “stab in the back” by the Asian giant are rife.

The classified documents, which were obtained by the Financial Times, they describe a threshold (threshold) for the use of tactical nuclear weapons that is lower than what Russia has publicly admitted, according to experts who have reviewed and verified the documents.

These are 29 secret Russian military files compiled between 2008 and 2014, including scripts for war games and presentations for naval officers, which discuss the operating principles for the use of nuclear weapons.

The criteria for a possible nuclear response range from a hostile invasion of Russian territory to more specific retaliatory launch scenariossuch as the destruction of 20% of Russia’s nuclear submarines.

“This is the first time we have seen documents like these publicly”, said Alexander Gabuev, director of the Carnegie Russia Eurasia Center in Berlin. “They show that the operational limit to the use of nuclear weapons is low enough if the desired effect cannot be achieved by conventional means’.

Russia’s tactical nuclear weapons, which can be launched by missiles from land or sea or from aircraft, are designed for limited battlefield use in Europe and Asia, as opposed to the larger “strategic” weapons intended to target the US. Modern warheads can still release far more energy than the weapons dropped on Nagasaki and Hiroshima in 1945.

Although the records date back 10 years and more, experts claim that they remain relevant to current Russian military doctrine. The documents were presented to the FT by Western sources to avoid a nuclear conflict between them.

The defensive schemes are revealing the deep suspicions about China that prevail in Moscow, even as Putin began to forge an alliance with Beijing that as early as 2001 included a nuclear non-use agreement as a first strike.

Over the years, Russia and China have deepened their cooperation, particularly since Xi Jinping took power in Beijing in 2012. The war in Ukraine has consolidated Russia’s status as the junior partner in their relationshipwith China giving Moscow a vital economic “lifeline” to smooth the fallout from Western sanctions.

However, although there was a rapprochement between the two countries, the training material shows that Russia’s Eastern Military Region was testing several scenarios depicting a Chinese invasion.

The drills offer a rare glimpse into how Russia views its nuclear arsenal as a cornerstone of its defense policy – and how it trains forces to be able to deliver a nuclear first strike under specific battlefield conditions.

An exercise outlining a hypothetical attack by China notes that the Russia, named “Northern Federation” for the purposes of the war game, could respond with a tactical nuclear strike to stop the ‘South’ to unleash a second wave of invasion forces.

“The order was given by the commander-in-chief… to use nuclear weapons... in case the enemy develops a second wave and the South threatens to attack further in the direction of the main strike”the document states.

China’s foreign ministry denied there were any grounds for suspicion about Moscow. “The Treaty of Good Neighborliness, Friendship and Cooperation between China and Russia has legally established the concept of eternal friendship and non-enmity between the two countries”a spokesman said. “The ‘threat theory’ doesn’t ‘sell’ to China and Russia”.

Putin’s spokesman said on Wednesday: “The key issue is that the threshold for the use of nuclear weapons is absolutely transparent and clarified in the doctrine. Regarding the documents mentioned, we strongly doubt their authenticity”.

A separate educational presentation for officers of the Russian navyunrelated to war games with China, outlines broader criteria for a possible nuclear attack, including a hostile landing on Russian soil, the defeat of the units responsible for security of border areas or an imminent enemy attack using conventional weapons.

The slides summarize the threshold as a combination of factors where losses suffered by Russian forces “would irreversibly result in their failure to stop the major enemy offensive,” a “critical situation for the state security of Russia”.

Other possible conditions include the destruction of 20% of Russia’s underwater strategic ballistic missilesof 30% of its nuclear-powered attack submarines, three or more cruisers, three airfields, or simultaneous attack on main and reserve coastal command centers.

The Russian military is also expected to be able to routinely use nuclear weapons for a wide range of objectives, including “preventing states from using aggression […] or de-escalation of military conflicts’, ‘removal of aggression’, preventing Russian forces from losing battles or ground, and to make the Russian navy ‘more effective’.

Putin said last June that felt “negative” about using tactical nuclear strikes, but then boasted that Russia had a larger non-strategic arsenal than NATO countries. The US has estimated that Russia has at least 2,000 such weapons. But Putin himself added that neither criteria was likely to be met, and rejected public calls from hardliners to lower the limit.

Although Moscow has reached out to Beijing after planning the war games and has moved forces from the east into Ukraine, continued to strengthen its eastern defenses. “Russia continues to build up its nuclear arsenal in the Far East near its border with China,” said William Alberki, director of strategy, technology and arms control at the International Institute for Strategic Studies. “Many of these systems only have the range to hit China.”

Russia still behaves according to the “theory of use” of nuclear weapons set out in the documents, Alberki pointed out. “We have not seen a fundamental rethink,” he noted, adding that Russia likely worries that China may seek to take advantage of any distraction by Moscow “to push the Russians out of Central Asia.”

Documents reflect patterns seen in drills regularly conducted by the Russian military before and after Putin’s 2022 invasion of Ukraine. Alberki, who has worked for NATO and the US Department of Defense on arms control, pointed to examples of Russian drills held in June and In November last year, using nuclear-tipped Iskander missiles in two areas bordering China.

While Russia’s president has the sole authority to launch a nuclear first strike, the low threshold for tactical nuclear use set out in the documents is in line with a doctrine some Western observers refer to as “escalation with the goal of de-escalation”.

As part of this strategy, a tactical weapon could be used to try to protect Russia from the to engage in an extended war, particularly one in which the US could intervene. Using what he calls “fear provocation,” Moscow will seek to end the conflict on its own terms by shocking the country’s rival with the early use of a small nuclear weapon—or securing a settlement through the threat of doing so.

“They talk about ‘sobering’ their opponents – to shake them off the ‘intoxication’ of their early victories by introducing nuclear weapons,” Alberki said. “The best way they think they can do that is to use what they call lower ‘dose’ nuclear weapons at a much lower combat level to prevent escalation.”

Ukrainian officials claimed that Putin’s nuclear threats convinced US and other allies not to arm Kiev more decisively early in the conflict, when NATO’s advanced weapons could have turned the tide in Ukraine’s favor.

Alberki commented that Russia will probably have a higher limit for using tactical nuclear weapons against Ukraine, which does not have its own nuclear capability or the ability to launch a land invasion on the same scale as it does against China or the US.

Russian leaders believe that while a nuclear strike against China or the US could “tame”, a nuclear strike in Ukraine is likely to escalate the conflict and lead to immediate US or UK intervention, Alberki added . “This is absolutely the last thing Putin wants.”