The Ukrainian Ministry of Foreign Affairs early Monday morning accused the United States of "excessive caution" for ordering family members of Kyiv Embassy staff to leave the country, as Russia gets closer to invading Ukraine by the day. 

"We have taken note of @StateDept’s decision re departure of family members of @USEmbassyKyiv staff," Ukraine spokesman Oleg Nikolenko tweeted. "While we respect right of foreign nations to ensure safety & security of their diplomatic missions, we believe such a step to be a premature one & an instance of excessive caution."

The United Kingdom is also bringing home "Some Embassy staff and dependents" due to the "growing threat from Russia." 

EUROPEAN UNION NOT FOLLOWING US LEAD IN EVACUATING UKRAINE EMBASSY STAFF, OFFICIAL SAYS

In a subsequent tweet, Nikolenko highlighted that the European Union is leaving its diplomatic staff and their families in Ukraine. 

The posts from Nikolenko come as the United States ordered family members of employees at the United States Embassy in Kyiv to leave the nation on Monday. It also authorized the voluntary departure of U.S. government employees in Ukraine. The State Department issued a "Do Not Travel" advisory for Ukraine "due to increased threats of significant Russian military action against Ukraine." 

Russian President Vladimir Putin

Russian President Vladimir Putin speaks during a news conference after his meeting with President Joe Biden in Geneva, Switzerland, on June 16, 2021. (AP Photo/Alexander Zemlianichenko, Pool)

As Russia, led by President Vladimir Putin, amasses more and more military personnel and equipment on Ukraine's border, the United States and other western allies are sending military assets to North Atlantic Treaty Organization (NATO) members near Ukraine. 

NATO said that it is "sending additional ships and fighter jets" to Eastern Europe. This includes F-16s from Denmark, naval forces from Spain, and F-35s from The Netherlands. Meanwhile, the United States is considering "increasing its military presence" in Eastern Europe – potentially with thousands of troops – and France is ready to send troops to Romania, which borders Ukraine to the south. 

NATO SENDING FIGHTER JETS AND SHIPS TO EASTERN EUROPE 

The United States has also already started sending "lethal aid" to Ukraine as the Eastern European country faces what appears to be an imminent attack from Russia. It may also send naval vessels to visit other American allies who are threatened. 

U.S. President Joe Biden

President Biden delivers remarks from the White House, Jan. 13, 2022. The U.S. provided "lethal aid" to Ukraine as a likely invasion from Russia looms. (Reuters/Kevin Lamarque/File Photo)

"I welcome Allies contributing additional forces to NATO. NATO will continue to take all necessary measures to protect and defend all Allies, including by reinforcing the eastern part of the Alliance," NATO Secretary General Jens Stoltenberg said. "We will always respond to any deterioration of our security environment, including through strengthening our collective defence."

Ukraine's territory has long been in Putin's crosshairs, especially amid recent NATO considerations of potentially allowing Ukraine to join the alliance. It is one of several post-Soviet republics in the region that shifted toward an alliance with the west after the collapse of the Soviet Union. 

Putin was in the Soviet KGB for many years before beginning his political career, and has said the collapse of the Soviet Union was the "greatest geopolitical catastrophe" of the 20th Century. 

Members of Ukraine's Territorial Defense Forces

Members of Ukraine's Territorial Defense Forces, volunteer military units, train in a city park in Kyiv, Ukraine, Saturday, Jan. 22, 2022. (AP Photo/Efrem Lukatsky)

Putin also stresses Russian ethnic and cultural influences in Ukraine as reasons why it should be part of Russia. That was a significant part of the justification Russia used when it illegally annexed the Crimea region of Ukraine in 2014. 

President Biden has warned there would be consequences for Russia if it invades Ukraine. But he also last week appeared to say that the U.S. might not respond forcefully to a "minor incursion" by Russia. That statement tipped off a wave of outrage both inside and outside the United States, followed by an effort by the White House to clean up the president's comments. 

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"I've been absolutely clear with President Putin. He has no misunderstanding, if any, any assembled Russian units move across the Ukrainian border, that is an invasion," Biden said, adding that this would "be met with severe and coordinated economic response that I've discussed in detail with our allies, as well as laid out very clearly for President Putin."

While NATO and the United States are fortifying allies, including the Baltics, it is almost certain the western alliance will not be sending troops into Ukraine itself, where they would be at risk of a potentially major military engagement with Russia. 

Fox News' Lucas Tomlinson, Jennifer Griffin, and The Associated Press contributed to this report.