Europe’s migrant crisis could become "even more volatile, unpredictable or large-scale" if Russia weaponises it, police chiefs warned.

Europol said the "instrumentalisation of migration has become a highly visible new factor" in the battle to restore control of national borders.

The agency admitted it is a "consequence" of Russia’s invasion of Ukraine, and the West’s support for Kyiv.

This, they say, plays into the smugglers’ hands as they will have more potential customers.

Europol said: “The instrumentalisation of migration has become a highly visible new factor at play today and is expected to further expand in the future.

“This is a further consequence of the Russian war of aggression against Ukraine and its implications for the regional and global geopolitical situation.

“Hybrid threat actors misuse the migratory situation to destabilise the EU and its Member States, thereby also providing additional business opportunities to criminal players in the field.

“Against the backdrop of today’s volatile and uncertain global context, migrant smuggling is expected to remain a profit-making criminal business.

“Demand is likely to remain high as migratory flows – due to economic, geopolitical, conflict, environmental or other reasons – will continue to be directed towards or via the EU.

“The migrant smuggling landscape may become even more volatile, unpredictable or large-scale if irregular migrants continue to be instrumentalised by hybrid threat actors to destabilise society.”

Finland accused Russia of handing out bicycles and foot-scooters to migrants to help them cross the border as part of a plan to destabilise Europe.

And Belarus was accused of handing out visas to Iraqis, who were then encouraged to travel to Poland.

In 2022, Italian intelligence reports said that Wagner Group, the Kremlin’s mercenary unit, organised boats of migrants to set off from Libya.

The expansion of the EU’s open borders scheme – the Schengen Zone – on January 1 has led to a new “route” through the Balkan region in recent months.

Smugglers are exploiting the changes by taking migrants through Bulgaria, into Romania, the Daily Express understands. Criminal gangs are effectively able to exploit a 400-mile land and avoid stringent border checks along Bulgaria’s border with Serbia.

Law enforcement chiefs are said to be particularly concerned by this development after years of intensive efforts to stop networks crossing from Turkey into Bulgaria and Greece.

A Home Office source said: “We have to keep close monitoring of any changes in the routes smugglers might be taking.

“We’re working with partners, law enforcement and intelligence to tackle these gangs, this includes work across the Western Balkans.”

Some 22,000 migrants are believed to have passed through the Western Balkan route into Europe last year.

Mr Lammy warned smugglers in the region are “becoming increasingly violent in their determination to make as much money as possible”.