North Atlantic Treaty Organization (NATO)’s Supreme Allied Commander Europe (SACEUR) Air Force Gen. Tod Wolters announced Friday that NATO has activated its Response Force, setting off a request for its members to supply forces as the alliance seeks to defend itself against any Russian attack.

The Pentagon on Friday said it could not provide any specifics on American military units, timelines, or schedules until NATO communicates what it will need.

President Joe Biden has already ordered 12,000 American forces from the U.S. to Europe, and has shifted several thousands more from Germany to the east in recent weeks. Some of those forces are expected to serve as part of the task force.

Biden has promised U.S. forces would not be fighting in Ukraine but said the U.S. would defend NATO allies.

Ukraine is not a NATO member, but other NATO members who are former Soviet Union countries — namely Estonia, Lithuania, and Latvia — are worried. Those nations and several others invoked Article 4 of NATO’s founding treaty this week, which allows for nations who feel threatened to trigger discussions for defense planning.

Ukrainian police officers outside a residential building damaged by a missile on February 25, 2022, in Kyiv, Ukraine. Yesterday, Russia began a large-scale attack on Ukraine, with Russian troops invading the country from the north, east, and south, accompanied by airstrikes and shelling. (Photo by Pierre Crom/Getty Images)

The activation of the response force, also known as the Very High Readiness Joint Response Force, comes after those discussions.

Wolters said in a statement on Friday afternoon:

In response to Russia’s unprovoked and unjustified invasion of Ukraine, the Alliance has operationally aligned its maritime, land, air, space, and cyber forces to defend our NATO sovereignty. With the response plans approved by the North Atlantic Council and in line with the evolving security environment, we are now employing elements of the NATO Response Force.

This is an historic moment and the very first time the Alliance has employed these high readiness forces in  deterrence and defense role. They represent a flexible, combat credible force that can be employed in multiple ways and we are utilizing fully their inherent agility.

Wolters did not say what the task force would do but said Allied military forces would “posture and exercise to increase our readiness and interoperability.”

“Your soldiers, sailors, airmen, and marines stand ready to protect every meter of Allied territory,” he added. “The Alliance remains steadfast in our collective commitment to shield and protect each other. Moving forward, we are prepared to leverage the strength of all our forces to defend the Alliance.”

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