PARIS -- The Louvre Museum in Paris was closed to the public on Sunday "for exceptional reasons" following a robbery in which nine items of great historical value were stolen, French authorities said. No injuries were reported.

At around 9:30 am local time, a gang of four burglars broke into the museum's Apollo Gallery — home to the French Crown Jewels and other treasures — by smashing the gallery's windows with angle grinders after hoisting themselves up from outside on a cherry picker.

Among the robbery's targets were a sapphire necklace from the jewelry of Queen Marie Amelie and Queen Hortense and a tiara from Empress Eugenie. During their escape, the gang abandoned one of the nine stolen items, which was found damaged near the museum.

French Interior Minister Laurent Nunez, who visited the scene, described the stolen artifacts as being of "inestimable" heritage value. The Louvre and the Ministry of Culture are working to compile a detailed list of the stolen items and assess their value. Nunez said he was "hopeful" that the perpetrators, who fled on a scooter, would be apprehended "very quickly."

"We are well aware that French museums are highly vulnerable," the interior minister said when asked about possible flaws in the surveillance system.

The Louvre's management had previously warned of infrastructure problems affecting the preservation and security of its collections, pending a major renovation program.

Culture Minister Rachida Dati told the television network TF1 that "organized crime today targets works of art, and museums have become targets."

French President Emmanuel Macron condemned the robbery on X, calling it "an attack on a heritage that we cherish because it is our history." He said the perpetrators would be brought to justice.

The last recorded theft at the Louvre occurred in 1998, when a painting was stolen in broad daylight and has not been recovered.