The crew of the Xelo vessel had issued a distress call on Friday evening and sought shelter in Tunisian waters from bad weather before going down in the Gulf of Gabes in the morning, the authorities said.
Environment Minister Leila Chikhaoui said on Saturday that “the situation is under control” in an interview aired on state television.
“There are minimal leaks, which are not even visible to the naked eye and fortunately the oil is evaporating, so there should not be a disaster in the Gulf of Gabes,” said Mohamed Karray, spokesman for a court in Gabes.
The spokesman had said earlier that the tanker carrying 750 tonnes of diesel had issued the distress call before it “sunk this morning in Tunisian territorial waters”.
The Equatorial Guinea-flagged Xelo was headed from the Egyptian port of Damietta to the European island of Malta when it requested entry to Tunisian waters.
The tanker is 58 metres (63 yards) long and nine metres wide, according to ship monitoring website vesseltracker.com.
It began taking water around seven kilometres (over four miles) offshore in the Gulf of Gabes and the engine room was engulfed, according to a Tunisian environment ministry statement.
It said Tunisian authorities evacuated the seven-member crew.
– Polluted waters –
Environment Minister Leila Chikhaoui was travelling to Gabes “to evaluate the situation… and to take necessary preventive decisions in coordination with the regional authorities”, a ministry statement said.
Authorities have activated “the national emergency plan for the prevention of marine pollution with the aim of bringing the situation under control and avoiding the spread of pollutants”.
Court spokesman Karray said the Georgian captain, four Turks and two Azerbaijanis were briefly hospitalised for checks and were now in a hotel.
The defence, interior, transport and customs ministries were working to avoid “a marine environmental disaster in the region and limit its impact”, the environment ministry said.
Before the ship sank, the ministry had described the situation as “alarming” but “under control”.
The Gulf of Gabes was traditionally a fishing area but activists say it has suffered from pollution from phosphate processing industries based nearby and the presence of a pipeline bringing oil from southern Tunisia.
The last maritime accident involving the country was in October 2018, when Tunisian freighter Ulysse slammed into the Cyprus-based Virginia anchored about 30 kilometres (20 miles) off the northern tip of the French island of Corsica, sending hundreds of tonnes of fuel spilling into the Mediterranean.
It took several days of maritime manoeuvres to disentangle the boats and pump some 520 cubic metres of propulsion fuel, which had escaped tanks.