Five people believed to be migrants drowned on September 25, 2025, while trying to cross the Kupa river on the Croatia-Slovenia border, Croatian police told news agency AFP.

The river, known as the Kolpa in Slovenia, runs about 90 kilometers southwest of Zagreb, Croatia's capital. Officers and members of the public pulled five survivors from the water. One officer arrived first and jumped into the river to help before reinforcements followed.

What do police know about the group?

The Croatian police statement said the group numbered around 20 people. Authorities gave no details on their origins or identities.

"14 of them managed to cross the river and are on Slovenia's territory," the statement read, according to AFP.

Where does the Kupa incident fit on the broader picture?

Croatia lies on the Balkan land route, used by people fleeing war and poverty in the Middle East, Asia, and Africa who seek to reach Western Europe. The Western Balkans form a major smuggling and trafficking corridor, strategically significant because the region connects entry points to destinations inside the European Union.

Frontex, the EU's border agency, recorded more than 12,500 detections along the route in 2025, a 42% drop from 2024. Detection numbers, however, do not always match the actual number of travelers. Migrants often try a border several times before moving on, and others are never counted at all.

Testimony from migrant aid groups in Slovenia and Italy, gathered over the last two years, indicates the number of people moving toward Italy stayed relatively stable in 2025, even as detected crossings fell.

Since 2014, the International Organization for Migration has recorded more than 400 people dead or missing along the route.

How are Croatia, Slovenia, and Italy coordinating their response?

In the days before the drownings, interior ministers from the three countries met in the Italian city of Pordenone. Slovenian Minister of the Interior and Public Administration Franci Matoz joined Italian Minister of the Interior Matteo Piantedosi and Croatian Deputy Prime Minister and Minister of the Interior Davor Božinović.

The agenda covered:

• Migration flows in the Western Balkans
• Implementation of the EU Pact on Migration and Asylum
• Frontex activity in the region
• Trilateral cooperation against human trafficking

Minister Matoz told his counterparts: "Slovenia is experiencing an increase in irregular migration. We therefore emphasise the need for consistent registration in the Eurodac system, as this is the only way to determine which country was the country of entry and to ensure that all countries take up their share of responsibility."

The trilateral format has run since 2023. Officials use it to coordinate joint work on internal security, migration management, and cross-border crime.

What is Croatia doing on its own border?

Croatia has intensified border control in recent months. In May 2025, authorities announced plans to build a migrant reception center at a former military airbase near the border with Bosnia and Herzegovina. Croatian police are also searching for a smuggling suspect linked to earlier migrant deaths in the country.