Theresa May will urge European countries to work together to tackle organised crime and corruption in an address to the Western Balkans summit.
The Prime Minister is expected to tell leaders that, through international cooperation, progress can be made that will “do justice” to the people of the region.
Mrs May will travel to Poznan, Poland, for the summit on Friday – which is likely to be her last foreign trip in office.
She is set to use her intervention to say crimes including money laundering, human and drugs trafficking, weapons trading, cyber-attacks and terrorism threaten lives in the UK and undermine security and stability in the Western Balkans.
“There is no doubt that serious and organised crime and corruption are security challenges we all face across Europe,” she will tell the summit.
“They can only be tackled by strong international cooperation.”
Mrs May will add: “The UK remains a committed friend of the region.
“I remain confident that by working together, we can make progress that will do justice to the peaceful, prosperous, European aspirations of the people of the Western Balkans.”
Countries agreed to develop an illicit finance and anti-corruption roadmap, proposed by the UK at a meeting of interior ministers on Thursday, which is hoped will strengthen institutions to stop the region being a refuge for organisations engaged in illicit activities.
Mrs May is due to argue that European countries play their part in increasing security in the region, and will urge countries to implement commitments made at the London Western Balkans Summit last year.