KARACHI, Pakistan (AP) _ A Greek-registered oil tanker that ran aground off Pakistan's coast more than two weeks ago has broken apart, and clean up crews were working to prevent a major oil spill, officials said Thursday.

``The ship has broken apart in two, but we have started stabilizing it,'' Iftikhar Rashid, federal communications ministry secretary, told reporters in the southern port city of Karachi.

``The worst is over, all possible oil spillage and all possible damage is done. The situation is not that bad,'' Rashid said.

The MT Tasman Spirit ran aground July 27 in monsoon rains and high tides. Officials were giving conflicting figures about the amount of oil the ship was carrying. One estimate put it at 67,000 metric tons (73,850 U.S. tons). The ship was carrying the oil for the state-run Pakistan Refinery Ltd.

According to Rashid, about 35,000 tons (38,600 US tons) of oil were left in tanks that had been secured before the ship's hull developed cracks Wednesday. According to Rashid's figures about 55,000 tons (60,600 US tons) of oil have been salvaged.

He refused to give figures about the amount of oil that has been spilled.

``We cannot give the exact figure because of legal complications like insurance,'' said Rashid. ``We are going to start working to stabilize the ship and prevent accidents.''

Residents in Karachi living near the sea have complained of nausea and headaches, and local doctors fear the crude oil spilled could become harmful.

``Both my son and wife started vomiting and complaining of headaches because of the smell from the beach,'' Anwar Ahsan, a local banker who lives in the Sea View apartment blocks that overlooks the Arabian Sea, said Thursday.

Driven away by the smell, Ahsan moved his family Wednesday to stay with relatives elsewhere in the city.

A second resident of the seaside apartment building, Shakil Ahmed, said that he too moved his family when the smell from the spill became unbearable.

Two ships _ one from Britain and one from Singapore _ arrived at the Karachi port on Wednesday to help with the cleanup. They carried special equipment to decontaminate the waters and prevent the spill from spreading further, said Brig. Javed Iqbal Cheema, head of Pakistan's National Crisis management cell.

Local doctors fear the crude oil could become harmful and toxic to humans if it gets oxidized in the water or in the air.

``This may cause not only nausea, headaches and throat infections, but may also hurt the human brain especially when one is exposed to toxins for a long time,'' said Dr. Wafay Shakir, a neurosurgeon at a Karachi hospital.

But government officials said residents were not in danger.

``We have talked to environmental experts and they say that there is no threat to people until they enter the sea water,'' Rashid said.

The government has hired three environmental experts, including one from Britain, to examine the site and assist with the clean up.

``We have called in the best possible experts, no one can say that we have not done enough,'' said Rashid.

All public beaches in Karachi have been shut down, with police and army Rangers, wearing face masks, cordoning off the main ones. Residents complained the move spoiled their celebrations Thursday of Pakistan's Independence Day.

Sohail Wazir Ali, who was trying to get to the beach, was stopped by police and his motorcycle confiscated.

``We celebrate Independence Day every year by going to the beach and now the police are stopping us,'' Ali said, adding that he was not concerned by the oil fumes. ``It doesn't matter because we breath in the city pollution and fumes every day.''