Wars, famines and economic woes have forced millions of migrants from the Middle East and Africa to attempt to make it into Europe over the past decade.
The peak of the crisis came in 2015, when the aftershocks of the Arab Spring - including the bitter civil wars in Syria and Libya - saw close to a million people arrive on European shores.
While this crisis has never gone away, it has hit the headlines once again this month because of a build up of migrants on Poland’s border with Belarus.
So what is going on in Eastern Europe and why has it led to fears of a potential conflict in the region?
Here’s everything you need to know.
Where is Belarus?
The country of Belarus is sandwiched between Eastern Europe and Russia.
It shares borders with Lithuania and Latvia to the north, Russia to the east, Ukraine to the south and Poland to the west.
Belarus was part of the Soviet Union (USSR) until its dissolution in 1991.
Unlike most of the other former Soviet states, Belarus has been under authoritarian rule for much of its post-Soviet existence and has retained strong political ties with Russia.
Alexander Lukashenko has been president since 1994 and is regarded as Europe’s last out-and-out dictator.
In the summer of 2020, his re-election for a sixth term, which was widely believed to have been rigged, led to mass protests in Belarus’ capital Minsk.
But thanks to Russia’s support, Lukashenko has been able to remain in power.
What is going on at the Poland Belarus border?
Thousands of migrants from countries like Iraq, Syria and Libya have been attempting to get into Poland from Belarus this autumn.
Previously, people have largely tried to enter the EU through Greece, via Turkey, and Italy - routes that are shorter and more direct.
It has led to suspicion among western leaders that this mass arrival of migrants has been manufactured by the Belarusian regime of Alexander Lukashenko, and possibly Vladimir Putin, to exacerbate divisions in the EU.
Poland’s populist ruling political party, the Law and Justice Party, has been at loggerheads with the EU since 2015 over judicial reform in the country.
The EU has accused Belarus of encouraging illegal border crossings as a form of retaliation against the bloc’s sanctions on the Lukashenko regime for its crackdown on domestic protests after his disputed re-election last year.
These sanctions have targeted the interests and assets of senior officials in the country.
On Monday, an additional package of sanctions were agreed by the EU which were targeted at those thought to have brought on this migrant crisis, such as Belarus’s national airline Belavia.
Belarus has denied the allegations directed at it but says it will no longer stop refugees and migrants from trying to enter the EU.
There has been some dialogue between the Belarusian authorities and European leaders, although there has been no sign of a breakthrough as of yet.
Tensions have also ratcheted up between Polish authorities and migrants at the border, with Polish border guards firing tear gas at protesters on Tuesday (16 November).
A large makeshift migrant camp has sprung up on Belarus’ side of the border in the region of Grodno.
There are also fears that the stand-off could lead to a grave humanitarian crisis.
Temperatures in the region have dropped below freezing as winter approaches, leaving many of the migrants at risk of hypothermia.
Some deaths have already been reported, although exact figures are unknown given the dense forest cover along the border.
Why could the border crisis lead to conflict?
In a bid to counter the entry of migrants through its border with Belarus, Poland has deployed 15,000 troops backed by tanks, air defence assets and other weapons to the region.
It has led the Belarusian defence ministry to accuse Poland of an “unprecedented” military build-up.
Belarus has also threatened to cut off gas supplies to Europe from Russia.
On Wednesday (17 November) it temporarily limited oil deliveries through the Druzhba pipeline to Poland - although the state run company that looks after pipelines said this move had been due to unscheduled maintenance.
It came just a day after Germany temporarily halted its approval for the Nord Stream 2 gas pipeline from Russia - a project that has proven controversial as it would greatly increase the country’s reliance on Russian gas supplies.
In an interview with BBC politics programme The Andrew Marr Show, UK Chief of Defence staff General Sir Nick Carter said he was concerned the situation could escalate into “something really serious”.
“I think this is a classic case of the sort of hybrid playbook where you link disinformation to destabilisation and the idea of pushing migrants on to the European Union’s borders is a classic example of that sort of thing,” the General said.
He stressed that the UK and Nato “have to be on our guard”.
Britain has sent a small team of British armed forces personnel into Poland to provide “engineering support”.
The UK Government has publicly backed Poland and criticised Belarus.
The migrant crisis has also coincided with a build-up of Russian troops on the Ukrainian border.
According to the Ukrainian defence ministry, 90,000 Russian troops have amassed in the area, leading to fears an invasion could be about to take place.
Additional reporting by PA
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