LONDON (Reuters) - British Prime Minister Rishi Sunak will agree bilateral initiatives with Belgium, Bulgaria and Serbia on Thursday aimed at tackling organised crime linked to illegal migration, his office said.

At a European Political Community summit in Granada, Spain, Sunak will call for more coordinated action to address rising levels of illegal migration to Europe.

"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," Sunak said in a statement ahead of the meeting.

"We cannot allow criminal gangs to decide who comes to Europe’s shores."

Sunak has made stopping small boat arrivals across the Channel from France one of his top priorities ahead of an election expected next year. So far more than 25,000 people have been detected crossing the Channel this year.

The British leader and Italian Prime Minister Giorgia Meloni will also co-chair a small-group meeting on the sidelines of the EPC with other European partners to discuss joint action on tackling illegal migration and organised crime.

Britain's agreement with Belgium will include deploying new advanced detection technology to identify and disrupt people smuggling through Belgium and onwards to the UK, Sunak's office said.

Britain and Serbia will agree to enhance cooperation on prosecuting and disrupting criminal networks, intelligence sharing and operational cooperation on border management, Britain said, while its initiative with Bulgaria will include sharing information and practical support.

The European Political Community, the brainchild of French President Emmanuel Macron, comprises most countries on the continent, including non-EU states such as Britain, Serbia and Ukraine.

(Reporting by Kylie MacLellan; Editing by Gareth Jones)