Russia 'flooding Europe and UK with illegal migrants' in attempt to 'destabilise the EU and Britain'

He also blamed "neo-Marxist groups" and warned British teenagers that they faced jail and fines if they try to help such organisations at the Bulgaria-Turkey border.

Illegal migrants now use this border to enter Europe more easily after it became the EU's south-eastern external border when Bulgaria joined the EU's Schengen area in January.

The nation will be among others from Europe attending a summit hosted in London by Sir Keir Starmer on Wednesday.

It is expected that a discussion will be held on the subject of closer co-operation on tackling illegal immigration through the western Balkans.

Mr Mitov said some charities and NGOs were "maybe unwittingly" assisting Russian and people smugglers through their actions.

He told The Times: "They are neo-Marxist groups which are trying to justify their actions through philosophical or ideological constructs.

"Basically, let's get all the poor people from the world and let them establish themselves here, the absolute freedom of movement, the non-existence of borders and so on and so forth.

"So unfortunately, we do have challenges with such non-governmental organisations which, maybe unwittingly, take part in the operations of those hostile states and the criminal networks which smuggle people illegally into the territory of the EU and the UK.

"Illegal migration inflows are an instrument for hostile regimes to destabilise the European Union and the United Kingdom.

"They are aiming to destabilise the welfare systems. Plus, of course... through smuggling radicalised individuals, they create security issues for us."

Mr Mitov added that his nation needs strong borders as it had become "the gateway to Europe", saying: "Not it is time to build a home and preserve our internal freedoms.

"Not a fortress but a home which needs walls. Every house needs walls.

"Those walls need to be solid and there are gates through which every guest can enter."

Yvette Cooper, the Foreign Secretary, said: "It is clear that illegal migration into Europe and beyond is being driven not just by organised crime networks seeking to make a profit, but by hostile state actors seeking to destabilise Europe."

She added: "That threat is real, growing and very serious, and I have made clear that we need to expand and strengthen out international co-operation to tackle it together.

"We will therefore continue to support Bulgaria and our other Nato allies in securing Europe's external frontiers, and tacking every different type of threat we face from the Putin regime, including providing the specialist equipment, intelligence and training that will help our Bulgarian counterparts to defend their borders and disrupt these criminal operations."

It is also understood that Sir Keir will try to further talks with several Balkan leaders on "return hubs" during the summit on Wednesday.

The Prime Minister's hope is for countries such as Kosovo, North Macedonia, Bosnia Herzegovina and several countries outside Europe to accept rejected asylum seekers in return for money and intelligence.

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