Master jeweler Stephen Portier said the Louvre robbers might recut the stolen gems, which would significantly decrease their value.

Laurence des Cars is speaking for the first time since a gang of masked thieves - who remain at large - carried out Sunday's robbery.

Thieves used a stolen truck-mounted moving lift to scale the Louvre and steal royal jewels worth over $100 million in a lightning-fast Paris heist.

Officials say an outdated surveillance system left the world-famous museum in Paris vulnerable despite years of warnings.

The only camera monitoring the exterior wall of the Louvre where they broke in was pointing away from the first-floor balcony that led to Gallery of Apollo housing the jewels, she said. "We failed these jewels," she said, adding that no-one was protected from "brutal criminals - not even the Louvre".

Laurence des Cars, the Louvre's president and director, is set to testify about the heist before the French Senate's Culture, Education and Sport Committee on Oct. 22.

The French crown jewels robbed from the Louvre museum in Paris are likely lost forever, an art crime expert tells CBS News, even if the thieves are caught.

French investigators continued to search for eight stolen items after unidentified thieves carried out a daring daytime heist at the Louvre.