The Mona Lisa, Leonardo da Vinci's masterpiece of a mysterious woman with a slight smile, is deteriorating quickly, the Louvre Museum said Monday, announcing that an in-depth technical study was being conducted to determine why.

The thin, poplar wood panel on which the artwork is painted has become deformed since conservation experts last evaluated the condition of the painting, the Louvre said. The artwork is inspected every 1-2 years.

The Louvre said the condition of the Mona Lisa was causing "some worry" and that a new study has been launched, but one that will allow the painting to remain in the public eye.

"These analyses will take place in such a way as to allow the work to remain on public display," the Louvre said in a statement.

The study, to be conducted by the Center for Research and Restoration of Museums of France, is to better determine what materials the painting is made of and evaluate its vulnerability to climate changes.

The most famous painting in the world, the Mona Lisa is seen by nearly every one of the millions of visitors who set foot in the Louvre, according to spokeswoman Veronique Petitjean.

"We have 6 million visitors," said Veronique Petitjean. "Everybody sees it."

Experts believe the Mona Lisa, also known in Italian as La Gioconda, was painted over a long period beginning about 1505.

The admiration that the painting has endured throughout the ages is attributed to a number of factors: fascination with da Vinci's genius and persona; the artwork's stunning realism and technique; the mystery of the Mona Lisa's true identity; and the twists and turns in its history.

In 1911, an Italian painter stole the painting from the Louvre to get it back into Italian hands. After a lengthy police inquiry, which involved a long list of suspects including French poet Guillaume Apollinaire, the painting surfaced in Italy two years after it disappeared.

The theft was splashed across newspaper front pages around the world, helping to raise the artwork's fame even further.

(China Daily-Agencies April 27, 2004)