Britain on Wednesday sanctioned Balkans-based gangs and financiers helping facilitate small boat crossings, as migrant arrivals this year via the Channel were set to surpass the 2024 totals.
The sanctions, the latest under new UK powers as Prime Minister Keir Starmer faces intense pressure to curb the journeys. They were unveiled as he hosted European leaders at a Western Balkans summit.
They will discuss migration and wider European security as well as economic growth.
The Foreign Office said the asset freezes and travel bans targeted Balkans criminals involved in "illegal migration to the UK" as well as an international network involved in illicit finance for people-smuggling gangs.
Starmer took power in July 2024, vowing to "smash the gangs" behind nearly a decade of growing cross-Channel small boat migration.
The crossings are fuelling the rise of the hard-right in the UK and growing domestic tensions over immigration.
But the centre-left Labour leader has struggled to stem the perilous journeys, which have cost dozens of migrants their lives in recent years. The 2024 total of 36,816 arrivals is due to be surpassed Wednesday following new reported crossings.
The London summit included fellow European leaders, including Germany's Friedrich Merz and EU Foreign Affairs chief Kaja Kallas.
Starmer, opening the talks, called the Balkans region Europe's "crucible".
It is "the place where the security of our continent is put to the test", he said. The talks would include looking at how to tackle Russia's "malign influence", alongside rooting out corruption, he added.
Announcing the sanctions in an earlier statement, Starmer noted there was "a criminal route through the Western Balkans bringing illegal migrants to the UK, and we're determined to shut it down by working with European partners.
"Through a new Joint Migration Taskforce, British drones, and tougher sanctions, we're going after the smuggling gangs at every stage to put them out of business and deliver security for working people," he added.
Detailing the new curbs, the Foreign Office said they hit the Krasniqi network and its leaders, which it described as "a Kosovo-based organised crime group responsible for producing false documents and supplying them to criminal gangs".
It also sanctioned Nusret Seferovic, the alleged leader of a Croatian gang supplying false Croatian passports to Balkan gangs "to facilitate entry into European countries".
The UK government has also slapped curbs on the so-called ALPA network and individuals within it, accusing the organisation of procuring small boat components for people-smuggling gangs.
