BRUSSELS (AP) — NATO on Tuesday announced the formal suspension of a key Cold War-era security treaty in response to Russia’s pullout from the deal just hours earlier.

NATO said its action was required because “a situation whereby Allied State Parties abide by the Treaty, while Russia does not, would be unsustainable.”

The long-expected move came after both houses of the Russian parliament approved a bill proposed by President Vladimir Putin denouncing the CFE.

In February 2022, Moscow invaded Ukraine, sending hundreds of thousands of Russian troops into the neighboring country, which also shares a border with NATO members Poland, Slovakia, Romania and Hungary.

The statement further said that “even the formal preservation” of the treaty has become “unacceptable from the point of view of Russia’s fundamental security interests,” citing developments in Ukraine and NATO’s recent expansion.

In Brussels, NATO said that its allies who had signed on “intend to suspend the operation of the CFE Treaty for as long as necessary, in accordance with their rights under international law.” The alliance underlined that its members remain committed “to reduce military risk, and prevent misperceptions and conflicts.”

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