"The (Suez Canal) Authority requires certificates proving that the ship meets environmental standards for passing through the canal," a source with the authority was quoted as saying by the official MENA news agency.

The source denied that Egypt had not allowed the French aircraft carrier Clemenceau, an asbestos-insulated ship, to cross the Suez Canal on its way to a breakers' yard in India.

"The authority is not preventing any ship from transiting the canal but those transporting scrap metal must meet internationally agreed conditions to protect the environment," MENA said.

In Paris on Thursday, the defence ministry denied that the warship, which is being towed under French navy escort, had been officially refused access by Egypt, but acknowledged that it had been asked for more information.

"We are being asked for extra technical information, which we are in the process of providing," said ministry spokesman Jean-Francois Bureau.

"We have not been notified of a refusal decision at this point."

However, the head of Egypt's environmental agency, Mohammed Sayyed Khalil, had said Thursday that Cairo wanted written proof that the decommissioned aircraft carrier was not carrying hazardous waste in violation of the Basel Convention banning such trade.

"We have decided to prohibit the Clemenceau from entering Egypt's territorial waters," he said.

The dispatch of the Clemenceau by the French government to a shipbreaking yard in northwestern India has sparked fierce controversy in both countries, with critics accusing Paris of dumping its toxic waste on the Third World.

Two Greenpeace protestors had boarded the ship as it was being towed in international waters, climbing one of its masts to unfurl banners reading "Asbestos carrier: stay out of India".

Greenpeace has been fighting to block the ship's transfer for months, arguing that Indian shipyard workers will be at risk of asbestos poisoning.

The warship, which took part in the 1991 Gulf War, was taken out of service in 1997 when it was superseded by France's new nuclear-powered aircraft carrier, the Charles de Gaulle.

The ship left the southern French port of Toulon on December 31 after a long legal battle, and is due in India at the end of February.

According to the French government, the vessel is carrying 45 tonnes of asbestos insulation. According to the firm that helped partially decontaminate it before the trip, the amount is between 500 and 1,000 tonnes.

An Indian Supreme Court panel on January 6 temporarily blocked the ship's entry into Indian waters and said it would make a final recommendation in two weeks once it had obtained more information.

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