Indonesian police say four Russian sailors died and three others were hospitalized after drinking a potent alcoholic brew in Borneo island, where their ship is anchored.

Central Kalimantan police said the deadly liquor was purchased from a local man. The four died on Wednesday and Thursday and three others suffered from breathing problems, dizziness and vomiting.

The four dead included three men and a woman from a cargo ship called the Captain Kurbatskey, which is in Indonesia to take on a cargo of iron ore.