Russian President Vladimir Putin on Thursday morning authorized a full-scale attack on the country.

Hundreds of miles from the previous conflict zone in the east of the country, explosions erupted in cities. Dozens of casualties have been reported in the fighting on its borders with Russia.

President Joe Biden said Thursday that no US troops would be sent to Ukraine, which is not a member of NATO, but warned that the US and its allies willdefend every inch of NATO territory.

In a speech from the White House, Biden said that his forces would not be involved in the conflict with Russia.

As scores of Ukrainians flee to neighboring countries, the conflict has quickly expanded into the most serious armed conflict in Europe for at least a decade.

What is NATO?

The North Atlantic Treaty Organization was formed in 1949 to provide security against Soviet expansionism and encourage European political integration after World War II.

NATO is a collective security system in which member states agree to defend each other against external attackers.

When it was founded, the agreement included just 12 countries, but has since tripled in size. The alliance now includes 28 European countries.

The organization accused Putin of violating international law in an act of aggression against a peaceful country. NATO has agreed to take additional steps to strengthen deterrence and protect all allies, but the details of its next steps have not been made public.

The organization said in the statement that they stood together to defend each other.

NATO has supported the Ukrainians killed and wounded in the conflict, but has yet to offer any hint that it will intervene in Russia's assault against Ukraine.

In his speech on Thursday, Putin warned that the consequences of the Ukrainian invasion would be more severe than anything the Western nations have faced before.

Ukraine's capital city Kyiv moments after Russian President Vladimir Putin authorized a military operation in eastern Ukraine
Ukraine's capital city Kyiv moments after Russian President Vladimir Putin authorized a military operation in eastern Ukraine
Reuters

Ukraine is not a member of NATO, but it wants to be

The former Soviet country has expressed a desire to join NATO, but has yet to be formally admitted. The body has designated Ukraine as one of its enhanced opportunity partners, a title granted to non-member countries that have contributed to NATO-led operations and missions.

France and Germany were worried about the unrest in the country, and they were not the only ones.

After NATO granted membership to former Soviet nations in the late 1990s and early 2000s, Russian leaders were wary. In 2008 NATO announced its intent to admit both Georgia and Ukraine at a later time.

Putin said in 2008 that his inclusion in the alliance would be viewed as a hostile act toward Russia because of the country's former Soviet status.

NATO and its members have no legal obligation to act on behalf of Ukraine.

Ukrainian President Volodymyr Zelensky made a direct appeal to NATO members on Thursday after Russia invaded.

He asked the 27 leaders of Europe if Ukraine would be in NATO. We are not afraid of anything.

Belarus — Ukraine's northern neighbor and a close Russian-ally — is not a member of NATO

Russian forces were allowed to invade Ukraine via Belarus, thanks to President Alexander Lukashenko.

While Lukashenko has claimed that his troops are not involved in the conflict, Russian forces entered from the north with the help of the country's air defense system.

Lukashenko, dubbed "Europe's last dictator", said this week that his country's forces will join the action if necessary.

The Collective Security Treaty Organization is an intergovernmental military alliance that includes some post-Soviet countries.

A man holds a young girl in his arms.
The first train with Ukrainian refugees came to Przemysl, Poland on February 24, 2022.
Photo by Maciej Luczniewski/NurPhoto via Getty Images

Moldova has no plans to formally join NATO

Thousands of Ukrainian refugees have already arrived in Moldova, located to the southwest of Ukraine.

The president said that the borders of the country are open for Ukrainian citizens who need safe transit or stay.

The former Soviet country has no plans to join NATO despite its support for fleeing refugees.

The Republic of Moldova proclaims its permanent neutrality. The Republic of Moldova does not allow the deployment of armed forces of other states.

According to the alliance's website, the country cooperates with NATO on a range of issues, primarily in its efforts to reform and modernize its defense and security structures.

Poland has been part of NATO since 1999

Thousands of Ukrainian refugees seek solace in the NATO-protected, EU-nation as their neighbor becomes a key player in the ongoing conflict.

More than 5,000 US troops arrived in eastern Europe before the invasion, and the country was their primary destination. The New York Times reported that the defense ministry in Poland instituted a high alert level on Thursday.

In the wake of the Russian invasion, Poland expects to welcome another million Ukrainians. The country said on Thursday that it would open reception centers along the Ukrainian border in anticipation of more arrivals.

An analysis published in Foreign Policy speculated that Poland's capital, Warsaw, is set to become the linchpin of the West's efforts to project power in Eastern Europe.

A new battle line in Central Europe would be drawn if Putin were to take ultimate control of Ukraine. NATO countries have pledged to take action if one of their own is attacked, if Russian forces are stationed along Poland's eastern border.

US soldiers stand in a field.
US soldiers are exercising at a hill in Arlamow military base. American soldiers arrived in Poland after Pentagon announced additional forces needed.
Photo by Attila Husejnow/SOPA Images/LightRocket via Getty Images

Ukraine's three other western neighbors are members of NATO

NATO members Slovakia, Hungary, and Romania share a border with Ukraine.

In 1999, Hungary joined the organization, while Slovakia and Romania were granted membership in 2004.

All three countries are preparing to accept Ukrainian refugees.

Here is a full list of NATO members and the year they joined the organization:

  • Albania: 2009
  • Belgium: 1949
  • Bulgaria: 2004
  • Canada: 1949
  • Croatia: 2009
  • Czech Republic: 1999
  • Denmark: 1949
  • Estonia: 2004
  • France: 1949
  • Germany: 1955
  • Greece: 1952
  • Hungary: 1999
  • Iceland: 1949
  • Italy: 1949
  • Latvia: 2004
  • Lithuania: 2004
  • Luxembourg: 1949
  • Montenegro: 2017
  • Netherlands: 1949
  • North Macedonia: 2020
  • Norway: 1949
  • Poland: 1999
  • Portugal: 1949
  • Romania: 2004
  • Slovakia: 2004
  • Slovenia: 2004
  • Spain: 1982
  • Turkey: 1952
  • United Kingdom: 1949
  • United States: 1949