Crowds surge across a broken down fence as soldiers repel them violently. Freezing families huddle around fires on ground hard with frost. Children in thick winter jackets press up against a tangle of barbed wire. "Water, water, water," they chant. 

These are just some of the distressing images from the border between Poland and Belarus, where thousands of migrants are stranded. 

This is no ordinary migration crisis: Belarussian dictator Aleksander Lukashenko has deliberately weaponised migrants' suffering in an attempt to destabilise the EUEuropean Union. An economic and political union of 27 countries. . Desperate refugees are imported into Belarus and herded to the border, where they attempt to force their way into neighbouring countries.

These people are unwitting weapons in what the EU describes as Lukashenko's "gangster tactics" as he counters European sanctionsEconomic measures designed to punish a country, for instance by excluding it from trade. against his authoritarian state. More alarming, the campaign is supported by Vladimir Putin. Russia has now amassed 90,000 troops at its western borders and flown nuclear-capable bombers over Belarus.

Could this be the prelude to war? The US government believes so. Secretary of StateThe US government official in charge of foreign policy. Pompeo, who was formerly head of the CIA, has held the post since April 2018. Antony Blinken has warned Europe that Russia's manoeuvres are similar to those that foreshadowed its invasion of CrimeaA peninsula in southern Ukraine that was seized by Russian forces in 2014 and annexed to the larger country. seven years ago. "Russia may make the serious mistake of attempting to rehash what it undertook in 2014," he said.

The immediate threat is to Ukraine, but Putin's aggression is also aimed at Europe more broadly. Earlier this year, he called EU sanctions on Belarus a "provocation" and threatened that Russia's response could be "asymmetrical, rapid and harsh." If Russia invades Ukraine, some believe that EU countries could be next. Putin also has the power to close gas pipelines that Europe relies on for energy.

Russian threats against Ukraine are not new. Many Russians see the neighbouring country, which includes many Russian speakers, as a natural and historical part of their nation. Expansionism is also an established part of Putin's governing style: with the Russian economy struggling, he relies on wars to drum up popular support. 

But why would Russia choose this moment to strike? British MP Tobias Elwood gives two reasons. Firstly, he says, "the world is distracted by other events" such as Covid-19 and Cop26. Secondly, a disastrous withdrawal from Afghanistan has added to the sense that the West is weak: "the US has effectively stepped back from global interests security-wise; NatoThe North Atlantic Treaty Organisation was founded in 1949 to unite Western democracies in Europe and North America against the perceived growing threat of the USSR. It now has 31 members. is bruised."

This could give Russia a chance to escalate what two experts call an "undeclared war on the West." The risk, they say, could be "not just economic and political, but for some, existential".

Others analysts argue that previous such alarms have proved false and that war is too risky for Russia. "I don't think there's any piece of terrain in Ukraine," one analyst says, "that is important enough to justify the cost".

This is just saber rattling, some say: populists like Putin like to talk big, but really they're just putting on a show for their own domestic audience. A war between major powers would not be in any countries interests, so it's unlikely to happen.

That's missing the point, others respond: the fact that war would help nobody won't stop cynical leaders from using it to bolster their own power. If Europe and America take these threats lightly, a huge swathe of the democratic world could soon find itself at the mercy of ruthless authoritarians like Putin.

Aleksander Lukashenko - The president of Belarus is often described as "Europe's last dictator." He has ruled the country since 1994 by clamping down on free speech.

EU - Debates over migration have caused deep tensions in many European countries in recent years. Poland in particular is ruled by a far-right government that strongly opposes migration from outside the EU.

Sanctions - Economic restrictions designed to harm a country as a way of exerting diplomatic pressure. The EU stiffened sanctions against Belarus after Lukashenko cracked down on protests following his rigged election victory in 2020.

Nuclear-capable bombers - Planes able to carry nuclear weapons, of which Russia is estimated to have 1,600.

Secretary of State - The figure in the US government responsible for foreign policy.

Crimea - A disputed region that was part of Ukraine until 2014, when it was invaded by Russia. Russia now effectively controls the territory, although there is still much unrest.

Gas pipelines - Russia is the world's leading exporter of gas, which Europe relies on to fuel its power plants. There is currently major controversy in EU countries about a further gas pipeline being built across the Baltic, called Nord Stream 2.

Nato - The North Atlantic Treaty Organisation is an alliance of European and American powers. Historically its enemy is the Soviet Union, to which Russia is the successor state.