Divers on Sunday inspected the hull of a tanker loaded with 750 tonnes of fuel that sank off southeastern Tunisia, with no leak detected so far, officials said.

"With the improvement in weather conditions, a team of divers accompanied by the ship's captain and engineer who know its layout are on site to examine the hull," Mohamed Karray, spokesman for the court in Gabes city, which is investigating Saturday's sinking, told AFP.

The Equatorial Guinea-flagged Xelo was traveling from Egypt to Malta when it went down.

Images released by the environment and defense ministries showed divers heading for the site in the Gulf of Gabes, and then getting into the water at the scene that has been sealed off by Tunisia's military.

Defense ministry photos showed the vessel largely submerged.

The crew of the Xelo had issued a distress call on Friday evening and sought shelter in Tunisian waters from bad weather before going down, authorities said.

Environment Minister Leila Chikhaoui, who traveled to the port of Gabes on Saturday to help oversee the response, said the situation was "under control".

"We think the hull is still watertight and there is no leakage for the moment," she told AFP.

As a precaution, protective booms to contain any oil slick have been placed around the wreck.

The Tunisia branch of the World Wildlife Fund expressed concern about another "environmental catastrophe" in the region, an important fishing zone which has already suffered from pollution.

The tanker is 58 meters (63 yards) long and nine meters wide, according to ship monitoring website vesseltracker.com.

It began taking on water around seven kilometers (four miles) offshore in the Gulf of Gabes and the engine room was engulfed, according to the environment ministry.

It said Tunisian authorities rescued the seven-member crew, who received first aid and were being accommodated in a hotel.