PARIS - The Louvre's cameras failed to detect burglars in time to prevent their audacious daylight heist of some of France's crown jewels, the museum's director said on Wednesday, amid growing anger directed at officials over major security lapses.

The thieves broke into the world-famous Paris museum on Sunday using a crane to smash an upstairs window, then stole jewels worth an estimated 88 million euros ($102 million) before escaping on motorbikes. News of the robbery reverberated around the world, and prompted soul-searching in France over what some viewed as a national humiliation.

Laurence des Cars, the Louvre director, told senators that she had offered her resignation, but it had been refused by Culture Minister Rachida Dati, who has also come under fire as recriminations flew after the robbery.

Security efforts 'defeated'

"Despite our efforts, despite our hard work every day, we were defeated," Des Cars told a Senate committee.

Many in France and around the world have been baffled how four hooded assailants were able to drive up to the world's most visited museum, smash a second-floor window and make off with a handsome booty without getting caught. Ministers have admitted serious security lapses occurred.

"We did not detect the thieves' arrival early enough," Des Car said, blaming it on the fact that there were not enough cameras outside monitoring the perimeter of the Louvre.

The exterior security cameras do not offer full coverage of the museum's facade, she said, adding that the window through which the thieves broke in was not monitored by CCTV.

Des Cars said she had repeatedly warned that the centuries-old building's security was in a dire state. "The warnings I had been sounding came horribly true last Sunday."

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She pledged to establish no-parking perimeters in areas around the Louvre, upgrade the CCTV network and ask the interior ministry to set up a police station inside the museum.

Four other French museums robbed recently 

The heist, on a Sunday morning after the Louvre had already opened to visitors, has prompted an assessment of security at museums across the country. Paris is home to some of the world's best-known cultural institutions, including museums like Orsay, Pompidou and Quai Branly which help sustain booming tourism.

At least four French museums have been robbed over the last two months, according to media reports.