President Biden's move to authorize calling up to 3,000 reservists to augment U.S. forces in Europe comes as the military struggles to recruit enough troops to the active-duty ranks.

The president's executive order last week authorized the secretary of defense and secretary of homeland security to call members of the Selected Reserve and Individual Ready Reserve to active duty "for the effective conduct of Operation Atlantic Resolve in and around the United States European Command’s area of responsibility."

The order follows Russia's invasion of Ukraine entering a new phase of unpredictability. 

Most notable was an apparent coup attempt by Russia's private military company, the Wagner Group, which ended with thousands of its fighters reportedly taking new homes in Belarus, raising fears about the vulnerability of NATO's eastern flank.

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President Biden and Volodymyr Zelenskyy

President Biden and Ukrainian President Volodymyr Zelenskyy on stage during the G-7 Declaration of Joint Support for Ukraine during the high-level NATO summit in Vilnius, Lithuania, July 12, 2023. Biden is calling to increase U.S. military forces in Europe. (Dominika Zarzycka/NurPhoto via Getty Images)

Russia's war with Ukraine has prompted the U.S. to beef up its presence in Europe, with the Pentagon deploying an additional 20,000 troops to the continent since the conflict began last year.

The increased rotations to international theaters has strained the military, which was already battling its worse recruiting crisis in decades when the war in Ukraine began. 

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While all branches of the military struggled to hit their fiscal 2022 recruiting goals, the Army was the only one to fall short of its objective. Earlier this year, the Army, Navy and Air Force all admitted they were likely to fall thousands of recruits short of meeting their fiscal 2023 targets. 

Only the Marine Corps, which is seeking to add 29,000 recruits in 2023, is expected to meet its recruiting targets.

Reached for comment by Fox News Digital, a Pentagon spokesperson said the move to call up reserves "was not related to recruiting."

military army

The Army, Navy and Air Force are expected to fall thousands of recruits short of meeting their fiscal year 2023 targets. (Fox News Digital)

According to Lt. Gen. Douglas Sims, troops called up to serve will not increase the number of service members in Europe but allow the military to pull qualified reservists to fill roles currently being filled by active members.

"As an example, over time, where we may have had someone from an active component organization doing something, that job now under these authorities may be something that a reserve component unit may be able to do," Sims said, according to a Military Times report.

Members of the Individual Ready Reserve, or IRR, are former active duty or reservist troops who, while not actively participating in military activities, are still under contract to be called up to active duty by executive order of the president.

According to a statement by the Army, these troops "are trained soldiers who may be called upon, if needed, to replace soldiers in active duty and Army Reserve units."

World leaders posing for a photo

NATO Secretary General Jens Stoltenberg poses for a photo with the participants of the NATO Summit in Vilnius July 11, 2023.  (Odd Andersen/AFP via Getty Images)

Speaking to Fox News last week, National Security Council spokesperson John Kirby said many of the reservists being called up will serve in "administrative functions" as the military continues to send members to Europe to reinforce NATO.

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"This basically is a realization of the fact that the president knows that the security environment in Europe is changed," Kirby said. "We’ve got to make sure that we’ve got the proper force posture to support an additional eastern flank presence for the long haul."