Russian President Vladimir Putin has authorized a new nuclear doctrine, bringing into force changes he first announced in September. The order was published on Tuesday alongside a revised version of the key military document.

According to the new doctrine, Russia may use nuclear deterrence to prevent aggression by hostile powers and military blocs that possess weapons of mass destruction or large arsenals of conventional weapons. Countries that provide their sovereign space for other parties to prepare and launch an attack against Russia are subject to the policy as well.

An attack by a single member of a bloc, including one that does not have nuclear weapons, will be considered an attack by the entire collective. The same would apply where a nation that does not formally belong to a military organization is backed by a nuclear power.

Russia’s goal is to make sure that “a potential aggressor realizes that retaliation will be inevitable” if the country were attacked, the doctrine says. Russian military allies will enjoy the same protection. The document lists ten threats that require counteraction through deterrence, ranging from nuclear arsenals in the possession of hostile parties, to potential unchecked proliferation of weapons of mass destruction and their delivery systems. Other threats include military buildup near Russia’s borders, the development of anti-ballistic missile systems, deployment of conventional weapon systems that can strike Russian territory, and potential sabotage plots to cause large-scale environmental disasters.

The list of triggers for nuclear retaliation now includes confirmed intelligence about a massive incoming attack using enemy aircraft, missiles and drones, once such weapons cross into Russian airspace.

The president of Russia remains the official making the decision on whether to use the country’s nuclear arsenal. He also has the authority to communicate his intentions and actions regarding such weapons to foreign nations.

The revised doctrine was published days after US President Joe Biden reportedly granted Ukraine permission to use long-range weapons donated by Washington for strikes deep inside Russia. Putin previously warned that such an attack would constitute a direct war between NATO and Russia.