Jewellery stolen from the Louvre in Paris in a daring daylight robbery has been valued at 88 million euros (£76m; $102m), a French public prosecutor has said, citing the museum's curator.

Laure Beccuau told RTL radio the sum was "extraordinary" but said the greater loss was to France's historical heritage. Crown jewels and pieces gifted by two Napoleons to their wives were among the items taken.

Thieves wielding power tools took less than eight minutes to make off with the loot shortly after the world's most-visited museum opened on Sunday morning.

With the thieves having not been caught more than two days on from the heist, experts fear the jewellery will already be long gone.

The items taken, previously described as having inestimable worth, include a diamond and emerald necklace Emperor Napoleon gave to his wife, a tiara worn by Empress Eugenie, the wife of Napoleon III, and several pieces previously owned by Queen Marie-Amelie.

Investigators found a damaged crown that used to belong to Empress Eugenie on the thieves' escape route - apparently having been dropped as they departed in haste.

Four masked thieves used a truck equipped with a mechanical lift to gain access to the Galerie d'Apollon (Gallery of Apollo) via a balcony close to the River Seine.

Two of them cut through a glass window on the first floor using a battery-powered disc cutter and entered the museum. They then threatened the guards inside, who evacuated the building.

The thieves had tried to set fire to their vehicle outside but were prevented by the intervention of a member of museum staff. They were seen making off on scooters.

French President Emmanuel Macron described the robbery as an attack on France's heritage.