Words by ITV News Content Producer Jocelyn Evans
Tensions between Russia and the West have reached critical levels over the past few weeks, over concerns Moscow is planning to invade Ukraine.
Russian troops have been amassing at the border with the former Soviet country for months, prompting NATO countries to respond by considering its own deployment of troops.
Already the US has put 8,500 troops on heightened alert over the issue.
Talks between the various parties have been taking place for the past few weeks, and are ongoing.
Here we outline who the key players are, and which important names to look out for.
The North Atlantic Treaty Organization (NATO) is a military alliance of 30 countries across Europe and North America. The US and the UK are in it - Russia is not.
Though Ukraine is not an official member, NATO has supported the country since it joined the North Atlantic Cooperation Council in 1991 after it gained independence following the collapse of the Soviet Union.
Earlier this month, NATO said: "A sovereign, independent and stable Ukraine, firmly committed to democracy and the rule of law, is key to Euro-Atlantic security".
Though the alliance's first aim is to resolve disputes peacefully, NATO has military powers if needed and acts as a collective defence under "NATO forces". These forces are made up of troops from various members.
Jens Stoltenberg is NATO's Secretary General - he's been in charge since 2014.
Ukraine has aspirations to join NATO written into its constitution, and NATO has said any sovereign democratic nation may apply to join if it wishes.
This has angered Russia who sees NATO as a threat and claims it would refuse to accept any further expansion eastwards.
President of Ukraine, Volodymyr Zelenskyy
Ukrainian President Volodymyr Zelenskyy has been in office since 2019, swapping a career in comedy to become a politician.
In his bid to get elected, Zelenskyy pledged to end conflicts between Russia and Ukraine - he's so far been unsuccessful.
He's also supportive of Ukraine joining both the EU and NATO, which is generally popular with a majority of Ukrainians.
Since the invasion began, he has refused to leave the country and remains in Kyiv despite heavy bombardment from Russian troops.
Foreign Minister of Ukraine, Dmytro Kuleba
As foreign minister, Kuleba is responsible for urging overseas governments to back Ukraine as tensions mount.
Since November 2021, he's been involved in diplomatic talks with European leaders in Brussels (where NATO is based) urging them to prepare for potential military action.
He's also keen to get Ukraine into NATO and, in an article for think tank Atlantic Council, argued the country was a strong candidate having "been successfully countering Russian aggression... protecting not only itself but a wider region between the Baltic and Black Seas."
NATO maintains it has an open door policy but aspiring members have to meet certain political, economic and military criteria before they can join.
President of Russia, Vladimir Putin
Synonymous with his country, Putin has been President of the country since 1999 (with a four year hiatus between 2008 and 2012 when he became Prime Minister due to rules around three consecutive terms).
In short, he has had political dominance in Russia for more than two decades - and in that time, Russian aggression against Ukraine has intensified.
Under his premiership, Russia invaded and annexed Crimea in 2014. The move was condemned for breaking international law and peace agreements signed by Russia. Putin's defence was that a "referendum" (condemned internationally as invalid) meant the people of Crimea had wanted to be under Russian control.
Putin is opposed to Ukraine joining NATO, claiming it would represent "NATO expansion" into the East.
He is claiming Russia is only reacting to Ukrainian aggression and has compared arming Ukraine to putting Russian missiles in Mexico.
In one of the most worrying developments early on in the conflict, he put his nuclear deterrent forces on high alert after Russia was hit with a raft of sanctions.
President of the United States, Joe Biden
Perhaps a name more familiar to readers, Joe Biden has also been involved in the series of talks held - and some mishaps too.
Following those December 2021 talks with Putin, the President the White House issued a statement saying: "President Biden voiced the deep concerns of the United States and our European Allies about Russia’s escalation of forces surrounding Ukraine and made clear that the US and our Allies would respond with strong economic and other measures in the event of military escalation."
Since then the US has been represented by Head of State Antony Blinken in ongoing talks, more on him shortly.
At his first press conference of 2022, President Biden misstepped after he said a "minor incursion" of Ukraine would elicit a lesser response than a full-scale invasion of the neighbouring country.
The White House moved quickly to clarify his comments, saying a "minor" incursion would still be a concerning breach of Ukraine's borders.
In his first State of the Union address to check Moscow’s aggression in Ukraine, he announced a ban on Russian planes in US airspace.
US Secretary of State, Antony Blinken
The face of US foreign policy Mr Blinken is the head of the US state department and had been holding regular talks with all interested parties about the crisis in Ukraine before the invasion.
He had been all over Europe for more diplomacy after a week of talking by US and Russian subordinates in January ended with no breakthrough.
Despite the strong words, Blinken also said he believed the US and Russia were on a "clearer path to understanding each other’s positions" after the meeting ended and talks were set to continue.
Blinken has a history with the situation too, he was involved in formulating the Obama administration's response to the annexation of Crimea in 2014.
Russian Foreign Minister, Sergey Lavrov
Russia's long standing foreign minister Sergey Lavrov has been at the head of Russia's diplomatic response to the crisis,
He has been both critical and cooperative of the west.
He recently met with British foreign minister Lizz Truss, and after a tense meeting he called her deaf while standing next to her.
He called the discussions "constructive and useful" but did add: "I can’t say whether we are on the right track or not" and said he believed the chance of a breakthrough was low.
Lavrov has been Russia's foreign minister since 2014 - during which time Russia annexed Crimea and tensions continued between the two countries.
During the annexation of Crimea, Lavrov was the Russian representative for talks with then-US secretary of state John Kerry. Back then, Lavrov told reporters following talks: "We have absolutely no intention of, or interest in, crossing Ukraine's borders".
In an interview with Al-Jazeera in early March, he reminded the world about the country's vast nuclear arsenal, warning: “A third world war will be nuclear, and devastating."
British Prime Minister Boris Johnson
Although the UK does not have the military might of the US or the connections to Russia and Ukraine that Germany and France do, Mr Johnson has still been keen to express support to Ukraine.
British and Russian relations have been nearly non-existent after the multiple poisonings of former Russian agents on British soil.
The UK has also been one of the biggest donators of military equipment to Ukraine during the crisis.
He has also been to Warsaw and Kyiv promising as much support as possible, including deploying more British troops to eastern NATO countries.
French President Emmanuel Macron
The leader of France recently my directly with President Putin, hoping he could find a way to diffuse the crisis.
France is seen as having generally better relations with Russia than the UK and the US.
Mr Macron was also one of the key architects of the Minsk agreement in 2015 that ended hostilities in eastern Ukraine.
German Chancellor Olaf Scholz
The new Chancellor of Germany is being subject to his first real test since taking office with the crisis in Ukraine.
Germany had been accused by its allies of being too weak on Russia due to its heavy dependence on Russian gas.
It has since cancelled the key Nord Stream 2 gas pipeline.
Belarus President Alexander Lukashenko
Lukashenko has come in for criticism for his part in supporting Vladimir Putin and the Russian invasion.
Russian troops have been based in southern Belarus and from there they have launched attacks on the north of Ukraine, including the capital Kyiv.
He has close relations with the Kremlin and peace talks had been held on the border of Ukraine and Belarus – after President Zelinskyy had refused to attend any hosted in Belarus, describing the country as a staging ground for the invasion.
China President, Xi Jinping
President Jinping, though not yet involved in any obvious way, will be paying close attention to developments.
He shares with Putin not just an ideological vision for a new global order, but their values align on human rights, freedom of speech and democracy, as our Asia Editor Debi Edward writes.
They are at the helm of authoritarian states in which there are widespread abuses and suppression of all three.