TUNIS: Some countries have offered to help Tunisia prevent damage to the environment after a merchant ship carrying up to one thousand tonnes of oil sank off the coast of Gabes, the Tunisian defence ministry said on Sunday.

The ship heading from Equatorial Guinea to Malta sank on Friday and the Tunisian navy rescued all seven crew members.

The vessel carried between 750 tonnes and one thousand tonnes of fuel and sent a distress call seven miles away from Gabes to which the Tunisian navy responded, officials said.

The defence ministry said in statement sent to Reuters that to control the environmental damage the Tunisian navy will work with countries that have expressed their desire to help.

Local media said that Italy had offered to help and that it is expected to send a naval vessel specialised in dealing with marine disasters.

On Saturday, Tunisian authorities opened an investigation into the ship's sinking, which the environment ministry said was caused by bad weather.

It said barriers would be set up to limit the spread of the fuel and cordon off the ship, before suctioning the spillage.

The coast of the southern city of Gabes has suffered major pollution for years, with environmental organisations saying industrial plants in the area have been dumping waste directly into the sea.

(Reporting By Tarek Amara; Editing by Muralikumar Anantharaman)