Azerbaijan rescued all nine crew members of an Iranian cargo vessel on Friday before it sunk in the Caspian Sea, Azerbaijan's state maritime agency said on Friday.
It was unclear what cargo the ship, the SHABAHANG, was carrying.
The maritime agency said the vessel had sent a distress signal on Friday afternoon after getting into trouble near the Azeri port of Lenkoran.
Two helicopters and a border patrol vessel had then rushed to the area and rescued the ship's crew, it said.
It gave no details about why the ship had run into trouble or where the vessel was heading.