Rishi Sunak has said he wants unity among European leaders to face down threats from Russia and to target people smugglers.
The Prime Minister will press his case as he attends the European Political Community summit in Granada, Spain, on Thursday.
Mr Sunak will co-chair a meeting with Italian prime minister Giorgia Meloni that is focused on “illegal migration and organised crime”, with the UK leader expected to raise the need for more coordinated action.
They said this will include working with Belgium to try to disrupt organised immigration crime and clandestine entry to the UK and efforts to cooperate further with Serbia on prosecuting and disrupting criminal networks.
Support for Ukraine will also be discussed, including work among European allies to provide weapons to Kyiv and the need for Black Sea grain shipments.
Mr Sunak is expected to confirm allocations of UK humanitarian aid to help Ukrainians over the winter.
The talks come as the UK claimed Russia may use sea mines to target civilian shipping in the Black Sea.
The UK Government said it was releasing its assessment of declassified information in a bid to deter any such incident occurring.
Artificial intelligence (AI) will also be discussed at the summit. A total of 47 heads of state and government have been invited.
Mr Sunak said: “Levels of illegal migration to mainland Europe are the highest they have been in nearly a decade. With thousands of people dying at sea, propelled by people smugglers, the situation is both immoral and unsustainable.
“We cannot allow criminal gangs to decide who comes to Europe’s shores.
“When it comes to facing down the threat from (Russian president Vladimir) Putin, confronting the risks and opportunities of AI or dealing with illegal migration, there is strength in unity.
“These issues transcend national borders and require creative Europe-wide solutions – that is what I will be discussing with my fellow leaders at the European Political Community summit in Spain today.”
Home Office figures show more than 25,000 people have been detected crossing the English Channel in small boats so far this year.
There were 45,774 arrivals in 2022.
The total number of small boat arrivals so far this year is around 23% below the equivalent number at this point last year.
Just over 33,000 people had made the crossing by October 2 2022, compared with 25,330 detected so far in 2023.
Mr Sunak has made stopping the crossings one of his key pledges for this year and last month he held talks with Italy’s hard-right leader Ms Meloni at the G20 summit.
The pair have become firm allies, having united over their stance of cutting irregular immigration into their countries.
The UK Parliament passed the Illegal Migration Act earlier this year following a lengthy tussle between the House of Commons and House of Lords.
The legislation aims to prevent people from claiming asylum in the UK if they arrive through unauthorised means.
The Government also hopes the changes will ensure detained people are promptly removed, either to their home country or a third country such as Rwanda.
The Government’s legal battle over its Rwanda deportation policy is set to be heard at the Supreme Court in October.
The Home Office is bringing a challenge after the Court of Appeal ruled in June that the multimillion-pound deal – which would see asylum seekers deported to the east African nation – was unlawful.