NATO allies, including White House officials, are concerned by Ukrainian President Volodymyr Zelensky’s decision to depart Kyiv for the Munich Security Conference this weekend, sources told Fox News Friday. 

Allies of the 30-member alliance are reportedly worried that Russia could exploit the president’s absence as tension in Eastern Europe has reached a boiling point not seen in decades. 

STATE DEPARTMENT CALLS EVACUATIONS IN EASTERN UKRAINE 'FALSE FLAG OPERATIONS,' WARNS OF DISTRACTIONS

Ukraine-soldier-donbas-russia

Image released by the Ukrainian Ministry of Defense on Thursday Feb 17, 2022 shows the frontline of Donbas, a conflict area with the Russian-backed separatists, during President Volodymyr Zelenskiy's visit to the Donetsk region in the east of Ukraine. (EYEPRESS via Reuters Connect)

Zelensky, who is set to meet with Vice President Kamala Harris on Saturday, is expected to be a key target if Russia does successfully invade Kyiv, sources confirmed. 

Zelensky's office confirmed his plans to attend the Munich conference early Saturday but said he will return to Ukraine hours later, according to Reuters.

President Biden said Friday he is "convinced" that Russian President Vladimir Putin has decided to invade Ukraine. 

In answer to questions from reporters as to whether he believed it would be a mistake for Zelensky to leave Ukraine at this time Biden said, "It may not be…the wise choice, but it's his decision."

"That's a judgment for him to make," Biden said. "It's in the pursuit of a diplomatic solution."

A senior U.S. defense official told Fox News Digital there is a strong possibility of a "significant invasion" by the Russian military in the coming days and Kyiv is its sites. 

President Joe Biden speaks about reaching 300 million COVID-19 vaccination shots, in the State Dining Room of the White House, Friday, June 18, 2021, in Washington. (AP Photo/Evan Vucci)

President Joe Biden speaks from the White House, Washington, D.C. (AP Photo/Evan Vucci)

The official said Russian military forces have left their barracks and that roughly 40-50% of Putin's troops have moved into attack positions — putting them within striking distance of the Ukrainian border. 

Putin now has 120-125 Battalion Tactical Groups amassed along Ukraine's border. All Special Forces have been mobilized, and rocket forces along with ballistic missile units are within range of the capital.

Destabilization efforts that the U.S. and NATO have warned against "has begun," the senior U.S. defense official said. 

Tensions in Eastern Ukraine, where Russia-backed separatists have clashed with the Ukrainian military since 2014, mounted this week and resulted in an exchange of artillery shelling that began Thursday.

KYIV MAYOR PLEADS WITH US, GERMANY OVER THREAT OF RUSSIAN INVASION: 'WE CAN'T DEFEND OUR COUNTRY'

A participant of an open civil defence exercise aims at a target, Uzhhorod, western Ukraine  (Serhii Hudak/Ukrinform/Future Publishing via Getty Images)

Leaders of two the separatist groups called for an evacuation of the breakaway regions of Donetsk and Luhansk, and leaders of the self-proclaimed republics claimed Friday that Russia has allegedly agreed to host evacuees.

Ukrainian officials and Russian-backed separatists have blamed each other for the attacks. 

The separatists Saturday declared a full military mobilization a day after women and children in the region had begun evacuating to southern Russia.

NATO allies are concerned Russia will use the violence there as a pretense to invade Ukraine.

The U.S. has not said who is responsible for the attacks, but officials have been sounding the alarm that Russia is laying the groundwork for an incursion.

The State Department this week pointed to false claims by Putin regarding human rights abuses, and a spokesperson told Fox News Digital the evacuation effort is just the latest "false flag operation."

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Harris reaffirmed that the Biden administration remains committed to engaging with Moscow, but said the focus of the security talks will be in maintaining a united front to deter Russian aggression.

"We have made clear that we remain open to diplomacy," she said from Munich Friday. "The onus is on Russia at this point to demonstrate that it is serious in that regard."

Fox News' Brie Stimson contributed to this report.