Robbers rammed their car into a mediaeval cathedral in southwest France early Monday, sawing through metal bars to grab silver chalices and other irreplaceable church treasures, local authorities said.
Initial investigations suggested the gang tied a tree trunk to the front of the car used to smash through a door of the cathedral in the town of Oloron-Sainte-Marie, town official Laurent Paris told AFP.
The edifice was registered as a UNESCO World Heritage site in 1998.
Once inside, the thieves helped themselves to chalices and other ceremonial objects, much of it gold, as well as a 17th-century nativity scene and a collection of clothes.
The treasures had been kept in a chapel, behind a steel grid whose "bars were sawn through," said Paris.
Oloron-Sainte-Marie is a favourite stopover for Catholic pilgrims headed for the Cathedral of Santiago de Compostela in Spain. It lies 50 kilometres from the Spanish border.
"The mayor was informed at about 2:00 am (0100 GMT) after locals woken by the noise and the cathedral alarm alerted the police," said Paris.
Witnesses saw three individuals take part in the heist, he added.
This was the first time that the cathedral had been attacked, the official said.
Experts will take stock of the loot taken, but Paris described the loss as "considerable".
"Over and above the monetary value, residents now find themselves cut off from their history and their heritage," he said.
The cathedral is best known for one of its oldest remaining features: a Romanesque portal sculpted in the 12th century.
The building burned in the 13th century, and again in the early 14th. It was pillaged at the end of the 16th during France's religious wars between Catholics and Huguenots.
Fixed and remodelled several times up until the 18th century, it was fully restored in the 19th century.