An Iraqi oil tanker was evacuated after a mine was discovered attached to its hull, and explosives experts were working to make it safe, Iraq's military said on Friday.
The tanker was in international waters about 28 nautical miles (52 km) off Iraq's coast in the Persian Gulf and supplying another ship with fuel when the device was discovered on Thursday afternoon, the military said in its statement.
"It's a complicated marine bomb with sensors that could cause a sudden explosion," a security source, who spoke on condition of anonymity, told Reuters.
"Our team has not dealt with such mines before and we asked for further assistance from a more professional bombs team," the source said.
Iraq's navy had secured the area and the ship has been isolated from other vessels, two other security sources said.
There have been several attacks on oil tankers in the Persian Gulf and the Red Sea in the last few years, amid rising regional tensions.
It was not immediately clear how the mine was attached to the tanker, which was being rented by an unidentified client from SOMO, Iraq's state oil marketing organisation, the military said.
In November an explosion damaged a Greek-managed tanker at a Saudi Arabian terminal on the Red Sea just north of the Yemeni border.