ZAGREB, Croatia — Authorities in Croatia said Monday that the wreckage of a small plane that had gone off the radar on the weekend was found, and that all four people on board were dead.

Search teams found the Cessna 182 plane near Brocanac, central Croatia, said the head of the civil protection teams, Damir Trut. He said police have launched a probe into the accident.

"As soon as the plane was spotted from above (by drone), search teams went to the scene," Trut said. "Unfortunately, it has been confirmed that all the passengers have died."

Trut did not reveal the nationalities of the victims of the crash. The state HRT television said they included a Swiss citizen, two Germans and a Croatian citizen.

The plane went missing on Sunday after taking off from the Adriatic Sea port of Split toward Germany. Local media reported that the weather in the area was bad and that the pilot sent an appeal for help before crashing.