NATO announced on Tuesday that it would suspend the operation of a Cold War-era security treaty after Russia formally exited the agreement.

It's the latest in a series of rising tensions between NATO and Russia after Moscow launched a full-scale invasion of Ukraine in February 2022.

The Treaty on Conventional Armed Forces in Europe (CFE), which was signed in 1990 and ratified two years later, sought to prevent Cold War rivals from building up military forces and equipment near their mutual borders.

Russia previously suspended its participation in the pact in 2007 and announced its intent to completely withdraw in 2015. Russia's exit from the agreement was finalized earlier on Tuesday.

Why did NATO suspend the treaty?

In a statement, NATO said that "a situation whereby Allied State Parties abide by the Treaty, while Russia does not, would be unsustainable."

The trans-Atlantic military alliance added that its members would halt their participation in the act "for as long as necessary."

A majority of NATO's 31 members signed the CFE.

The statement added that Russia's move to invade Ukraine and its ongoing war in the country were also "contrary to the [CFE] Treaty's objectives."

While Ukraine is not yet a member of NATO, several neighboring countries are in the military alliance — including Poland, Romania, Hungary and Slovakia.

The NATO statement added that its members are still committed to "reduce military risk, and prevent misperceptions and conflicts."

How has Russia responded?

Earlier on Tuesday, Russia's Foreign Ministry announced that the formal procedure to withdraw from the CFE was completed.

"Thus, the international legal document, the validity of which was suspended by our country back in 2007, has finally become history for us," the ministry said in a statement.

Russia said the actions of the United States, as well as efforts to expand NATO members, were to blame for Moscow's exit from the agreement.

"The CFE Treaty in its original form lost touch with reality," Russia's Foreign Ministry said.

In May this year, Russian President Vladimir Putin signed a decree that denounced the treaty, which drew swift condemnation from NATO.

Russia's invasion of Ukraine in 2022 and the ongoing war have brought relations between the US and Russia to lows not seen since the Cold War.

rs/sms (AP, Reuters)