An Iranian missile that struck a support ship in a friendly-fire incident has killed 19 sailors and wounded 15 others, Iran's navy said in a statement.
It said the incident occurred during a naval exercise in the Gulf of Oman yesterday, according to state TV
The friendly fire incident involving the Konarak vessel occurred near Bandar-e Jask, off the southern coast of the Islamic republic.
One report said the vessel had sunk after being hit by a missile fired by another Iranian warship.
"The vessel was hit after moving a practice target to its destination and not creating enough distance between itself and the target," state television said on its website.
The Konarak is a light logistical support vessel made in the Netherlands and purchased by Iran before the 1979 Islamic revolution.
Weighing 447 tonnes and 47 metres (154 feet) long, the Hendijan-class vessel is equipped with four cruise missiles, according to state television.
It was not immediately clear how many crew members were on board the warship at the time of the accident.
Tasnim news agency said in an English-language tweet that the Konarak had sunk after being hit by the missile fired by another Iranian warship.
Iran's armed forces in January shot down a Kiev-bound Boeing 737 passenger jet shortly after takeoff from Tehran, killing all 176 people aboard.
The military admitted to the catastrophic error, saying it came as Iran's air defences were on high alert after firing a barrage of missiles at US troops stationed in Iraq.
Iran launched the missiles in retaliation for the United States' killing of its top general Qassem Soleimani in a drone strike days before that.