BELGRADE, Serbia (AP) – Six people are missing after a boat carrying about a dozen migrants overturned while crossing the Danube on the border with Croatia, Serbian media reported Monday.

Serbian state television RTS said that the accident happened in the early morning as the migrants were trying to cross the Danube toward Croatia, which is a member of the European Union.

The remaining people on the boat managed to swim to the Serbia shore, the report said.

Other Serbian media reported that the missing migrants include two children. The Blic daily said Serbian police have organized a search.

Police are yet to issue an official statement.

The incident highlights the perils migrants face as they try to reach Western Europe while fleeing violence and poverty at home.

Thousands of migrants remain in the Balkans looking for ways to move on toward wealthy EU nations.