OSLO, Norway (AP) – Edvard Munch's masterpiece "The Scream" (pictured) goes back on display this week for the first time since it was stolen four years ago but has suffered permanent damage, museum officials said this week.

Masked gunmen stole the work and another Munch masterpiece, "Madonna'', in a brazen daylight raid on the Munch Museum in August 2004. Police recovered the paintings, considered priceless, over a year later. Two men have been convicted and sentenced.

The two works show signs of damage despite extensive restoration. At a preview of the exhibition called "The Scream and Madonna Revisited'', which opens today, water damage to the lower left corner of "The Scream" was clearly visible, as were scrapes to both paintings.

"There has been an extremely comprehensive process to restore the paintings. There was significant damage," said Gro Balas, a spokesman for the city of Oslo, which owns the museum. "There is still a moisture stain on 'The Scream' that cannot be repaired."

"The Scream" probably is the best known of Munch's emotionally charged works and was a major influence on the Expressionist movement. In four versions of the painting, a waif-like figure is apparently screaming or hearing a scream. The image has become a modern icon of human anxiety.

The museum said it concluded during its restoration of the unsigned and undated version of "The Scream" that it was most likely painted in 1910 rather than 1893 as believed earlier.

Balas and museum experts said they would keep looking for new restoration techniques.

Damage to "Madonna" included cuts and tears that were repaired by gluing threads of canvas in the damaged areas back together one at a time, said Mette Havrevold, who led the restoration effort. She said the damage that can still be seen in the painting will be repaired later in the year.

"It has been a long process, and the past year and a half has been marked by hard work and long days," she said about the restoration. Security was stepped up dramatically after the theft, with scanners and metal detectors like those used at airports installed at the museum. "The Scream" and "Madonna" were part of Munch's "Frieze of Life" series, in which sickness, death, anxiety and love are central themes. He died in 1944 at the age of 80.