The threat of Russia invading Ukraine grows as diplomatic relations between Moscow and the US feel the pressure, with Russia expelling the US’s second most senior diplomat in what the US State Department has described as “an escalatory step”.

“We can confirm that Russia expelled US Deputy Chief of Mission (DCM) to Russia, Bart Gorman,” a State Department spokesperson said.

President Joe Biden told reporters the threat of Russia invading Ukraine is “very high” and that he believes it could occur in the next “several days”.

Meanwhile, Western leaders have accused Russia of attempting a false-flag operation to discredit the Ukraine government, after it was reported that a kindergarten was shelled in a spate of shelling incidents in Donbas, in eastern Ukraine.

The Kremlin accused Ukraine of firing first, while Volodymyr Zelensky, Ukraine’s president, described the shelling of the kindergarten as “a big provocation”.

Tensions between Russia and Ukraine explained

Ukraine has been in conflict with pro-Moscow rebels in the country’s east since 2014, after the then-Ukraine leader decided not to join the European Union.

Russia has been accused of supplying the rebels with funds, weapons and even troops, but has denied this and said any soldiers who joined the movement did so voluntarily.

The rebel movement eventually grew so much that Russia was able to annex the peninsula of Crimea from Ukraine and take control of it, prompting the US and other North Atlantic Treaty Organisation (NATO) allies to send weapons to Ukraine.

Relations between the two nations have worsened since.

The most recent tensions have come after Ukraine said it wanted to join NATO to access more protection in the form of military force.

Why are the US and other Western countries involved?

Russia has demanded the West refuse Ukraine’s request – and prevent other former Soviet states from joining – believing its neighbour will try to regain control of Crimea among other concerns.

The US and NATO responded separately to Russia’s demands at the end of January, with Al Jazeera reporting that the US ruled out agreeing to exclude Ukraine and other eastern states from NATO.

However, Russia has replied to the US and accused the Western nation of ignoring its core demands and threatened to take “a military-technical response”.

What’s happening now?

Since January, as many as 130,000 Russian troops have been stationed along parts of the Ukrainian border, despite Russia repeatedly denying it is planning an invasion.

On February 12, the US warned “we are in the window where an invasion could begin at any time”.

Three days later, Russian president Vladimir Putin confirmed the troops would be pulled back from the border, despite Western intelligence reporting that its forces are continuing to build up.

Meanwhile, on February 16 a German convoy reached Lithuania as part of planned reinforcements for the country’s Germany-led NATO battlegroup, which has been authorised to defend Lithuania if a threat emerges.

Image: Getty Images

This article first appeared on OverSixty.