Sixteen kilometers (10 miles) of beachfront were littered with dead fish, turtles and mangrove seedlings -- the casualties from a 12,000-tonne oil slick from the Greek-registered MV Tasman Spirit that ran aground 100 meters (yards) from the commercial port on July 27 and has since broken up.

A total 12,000 tonnes of oil spilled into the sea from the tanker, including 5,000 tonnes used to operate the vessel, a senior Karachi Port Trust (KPT) official told AFP.

"An estimated 7,000 tonnes oil leaked from the original 62,500 tonnes while 5,000 tonnes of the ship's operating fuel also leaked into the sea," the official said, requesting anonymity.

President Pervez Musharraf has ordered an inquiry into the ship's grounding and break-up, while an international inquiry was already under way, port authorities said.

Residents of Karachi's seafront complained of severe respiratory problems caused by the oil fumes.

Aircraft sprayed dispersants to emulsify the water and booms and skimmers were out in full force to contain and suck the oil from the sea, witnesses said.

Even the sand along the shores has been blackened by the oil slick.

Some 20,000 tonnes of oil was transferred from the ship in a salvage operation before it was abandoned on Wednesday as the vessel began to break up.

An operation began late Saturday to transfer the remaining 35,000 tonnes of crude still intact in tanks in the ship's hold, KPT officials said.

"We have almost installed heavy equipment and smaller vessels alongside the doomed ship and will start transferring the oil in tanks from the ship," KPT Trust general manager Brigadier Iftikhar Arshad told AFP.

The oil transfer and clean-up efforts would take about 10 days, he said.

Environmentalists warned further oil leakage would aggravate the destruction already wrought by the oil slick.

"The damage has already been done," coastal ecosystems specialist Tahir Qureshi declared.

"Millions of mangrove seedlings on our eastern coast" have been destroyed, he told AFP.

"Now authorities should contain the situation otherwise the damage will be irreparable."

KPT chief Ahmed Hayat said authorities would impose a fine of 10 million rupees (172,000 dollars) on the ship's owner.

The costs of the clean-up operation and residual effects of the oil spill were to be absorbed by the ship's insurer, he said.

Arshad said the ship's 25-man crew, who left the ship on Tuesday, had been ordered not to leave Karachi while the inquiries are conducted.

"They are being questioned and they cannot leave until finalisation of the inquiry," he said.

The crew includes five Greek nationals and 20 Philippines nationals.

TERRA.WIRE