PARIS -- One week after four thieves swept through the Louvre in just seven minutes, the first arrests have been made in a case that exposed critical security weaknesses and wounded French pride.

The robbers arrived early last Sunday with a furniture-lift truck, sliced through a window of the Galerie d'Apollon, threatened guards and smashed through two display cases, stealing eight of France's crown jewels. The four suspects then sped off on scooters before police could respond.

Their take -- necklaces, tiaras and brooches once worn by France's long-departed royals and worth an estimated 88 million euros ($102.63 million) -- has left investigators racing against time to recover the missing pieces before they can be broken up and melted down or sold off.

The arrests were made on Saturday, with one man arrested while "preparing to leave the country" from Paris Charles de Gaulle Airport, Paris prosecutor Laure Beccuau said. AFP reports that two men were taken into custody on suspicion of organized theft and criminal conspiracy.

But seven days on, the daring heist that struck at the heart of France's national pride still raises uncomfortable questions about how the world's most visited museum was breached so easily.

The thieves parked a monte-meubles -- a truck mounted with a basket lift -- and used it to access a second-floor balcony, seemingly without drawing the attention of police or security.

The presence of such manned vehicles on the streets outside the Louvre is not unusual, museum security officers told NBC News, speaking prior to the arrests.

"Often there are window cleaners," said Vanessa Michaux Valora, a security officer at the museum for 21 years and a SUD union representative. "Now we're aware they no longer work at weekends, but at the time it didn't look unusual."

Julien Dunoyer, a security worker and union representative who also has two decades of experience at the museum, said there was work underway at a garden below the gallery, so it "wasn't a surprise that there was an elevator ladder."

"That's the problem with having lots of works in different locations," he said.

Valora and Dunoyer said they were working in different parts of the museum during the theft and were unaware a burglary had taken place when they were asked to evacuate people outside.

"We were asking ourselves whether it could be an attack and we needed to make sure everyone was safe," Valera said. "We didn't expect it to be so catastrophic. It's extremely shocking. We're really hurting."

Laurence des Cars, the Louvre director, told French senators Wednesday that the theft had exposed "weaknesses" in security.

"We did not detect the thieves' arrival early enough," she said, according to Reuters, blaming it on the fact that there were not enough cameras outside monitoring the perimeter of the museum.

After the theft at the Louvre, the SUD Culture labor union blamed the "destruction of jobs dedicated to security" and funding shortfalls for security equipment. Gallery attendants, ticket agents and security personnel at the museum staged a brief walkout in June, citing chronic understaffing and poor working conditions.

French President Emmanuel Macron announced a six-year renovation of the museum earlier this year, including money for security upgrades.

For a nation whose character is defined by proud displays of history and culture, the incident is being seen in some quarters as a national humiliation.

Macron called it "an attack on a heritage that we cherish because it is our history." He vowed to "recover the works and the perpetrators will be brought to justice," adding that "everything is being done, everywhere, to achieve this."

Alexandre Portier, the lawmaker leading the French parliament's inquiry into the theft, said the heist had left a "wound," with rising fears the treasures may never be seen again.

"I worry that as we speak the jewels have already been dismantled, chopped up, and risk being altered," Portier told NBC News prior to the arrests, in which case, "even if we find all the elements, we couldn't put back together the crowns and necklaces that were stolen."

The stolen items "belong to mankind, as part of our common history," he added, and "these may be lost, for all humanity."

One week on, a breakthrough in the Louvre heist that exposed weaknesses and wounded French pride