On one side of the border between Russia and Ukraine, more than 100,000 Russian soldiers are gathering in large numbers. In the south, thousands of Ukrainian citizens are being trained to repel what Western intelligence believes could be a Russian attack.
Why is there a conflict?
Ukraine - a part of Russian control for centuries before becoming a Soviet Republic - gained independence after the collapse of the Soviet Union in 1991. The country has since strengthened its increasingly close ties with the West.
The decision by pro-Russian Ukrainian President Viktor Yanukovych to reject an association agreement with the European Union to support closer ties with Moscow led to major protests that overthrew him in 2014.
In 2014, Russia annexed the Crimean peninsula after a Referral. Also in this year, a breakaway rebellion broke out in eastern Ukraine.
Ukraine and the West have accused Russia of sending troops and weapons to fight back against rebels. Moscow has denied it and said the Russian volunteers were part of the breakaway.
According to Kiev, more than 14,000 people have died in the fighting that devastated Donbass, Ukraine's eastern industrial center.
Moscow, for its part, strongly criticized the US and its NATO allies for supplying weapons to Ukraine and holding joint drills, saying such moves encourage those following Ukraine's tough line to seek to retake areas held by rebels by force.
In addition, Russian President Vladimir Putin has repeatedly said that Ukraine's aspiration to join NATO is a red line and expressed concern about the plan to establish military training centers for some NATO members in Ukraine. This would give them a military position in the region even if Ukraine does not join NATO, he said.
What does Russia want?
Russia does not want Ukraine to join NATO - and has made that clear in its list of security requests sent to the US last December. Russia has also asked to stop any NATO drills near its borders, and wants NATO to withdraw from Eastern Europe.
In December, President Putin said Russia was seeking assurance that NATO would stop expanding to the east and withdraw weapons systems threatening Russia in its vicinity of Russian territory.
Mr. Putin suggested that the West participate in substantive negotiations on this issue, adding that Moscow not only needs oral guarantees but also legal guarantees.
Ukraine's joining of NATO will require the approval of 30 countries to form the alliance.
The US and NATO have responded to Russia's request. Although Moscow and Western powers have not made details of the response public, Russia's main demands - banning Ukraine from becoming a NATO member and NATO not expanding further to the east - have been rejected.
Will Ukraine join NATO?
Ukraine is not a NATO member, but it wants to join the alliance. Ukraine is considered a NATO partner.
NATO said that before being considered a member, Kiev needs to root out evils such as corruption.
NATO Secretary General Jens Stoltenberg in December rejected Russia's request to cancel its 2008 commitment to Ukraine that it would become a member one day. Mr. Stoltenberg affirmed that when the issue is considered, Russia will not be able to deny the admission of Ukraine.
However, analysts say NATO allies, headed by the US, do not want to expand their military range in the region and further endanger relations with Russia.
While US Secretary of State Antony Blinken has voted in favor of Ukraine becoming a NATO member, President Joe Biden has been more vague about the issue.
Will there be a full-scale war?
The West has accused Russia of sending 100,000 troops to the Ukrainian border in preparation for an invasion of its close Western neighbor.
President Joe Biden said he "completely agree" on how to deal with Russia. The US sent 3,000 more troops to Germany, Poland and Romania over the weekend. The Pentagon has put 8,500 US troops on hold for deployment in Eastern Europe and NATO said it is sending ships and aircraft to enhance the region's defense capabilities.
Putin's spokesman Dmitry Peskov said the actions only increased the already tense atmosphere. The US is escalating tensions. We are monitoring these US actions with great attention," the spokesperson said.
Russia has denied any plans to invade Ukraine and accused the West of aggravating the situation.
What happens if Russia attacks Ukraine?
Many Western countries have expressed support for Ukraine but to different degrees. The US and UK have provided weapons, while Germany plans to send a field medical facility next month but will not transfer military equipment.
Public opinion also talked a lot about sanctions against Russia. On the one hand, the US and its European allies have publicly announced that they will impose unprecedented financial sanctions on Russia if it launches troops into Ukraine. Washington and London have even spoken about individual sanctions targeting President Putin.
Removing Russia from the SWIFT financial system, a money transfer system from one bank to another globally, would be one of the most difficult financial steps it could take, causing immediate and long-term damage to the Russian economy.
The move could cut Russia off from most international financial transactions, including international profits from oil and gas production, accounting for more than 40% of Russia's revenue.
The US also has one of the strongest financial weapons against Moscow, which is to prevent Russia from accessing the US dollar. The US dollar remains dominant in financial transactions around the world, with thousands of billions of USD traded daily.
Finally, the US is considering imposing export control measures, which could cut Russia off from the high-tech sector.
