An expression of concern by the environmental group Greenpeace about the carbon footprint was marred this week by real footprints — in a fragile, and restricted, landscape near the Nazca lines, ancient man-made designs etched in the Peruvian desert.
The Peruvian authorities said activists from the group damaged a patch of desert when they placed a large sign that promoted renewable energy near a set of lines that form the shape of a giant hummingbird.
The sign was meant to draw the attention of world leaders, reporters and others who were in Lima, the Peruvian capital, for a United Nations summit meeting aimed at reaching an agreement to address climate change. The meeting was scheduled to end Friday but negotiations were expected to continue into Saturday.
Greenpeace issued a statement apologizing for the stunt at the archaeological site, about 225 miles south of Lima. Its international executive director, Kumi Naidoo, flew to Lima, but the Peruvian authorities were seething over the episode, which they said had scarred one of the country’s most treasured national symbols.
“We are not ready to accept apologies from anybody,” said Luis Jaime Castillo, the vice minister for cultural heritage. “Let them apologize after they repair the damage.”
He added, however, that repair might not be possible.
Mr. Castillo said that about a dozen activists walked more than a mile through the desert to place the sign, made up of large yellow letters, near the hummingbird, one of the archaeological site’s best known figures. Entry to the area is forbidden.
The lines, etched into the desert more than 1,000 years ago by an ancient culture known today as the Nazca, form enormous figures spanning hundreds of feet, including birds and other animals, plants and geometric shapes. Their purpose remains a mystery but they are believed to have had a ceremonial use.
Mr. Castillo said that the desert around the lines is made up of white sand capped by a darker rocky layer. By walking through the desert, he said, the interlopers disturbed the upper layer, exposing the lighter sand below.
“A bad step, a heavy step, what it does is that it marks the ground forever,” he said. “There is no known technique to restore it the way it was.”
He said that the group walked in single file through the desert, meaning that they made a deep track in the ground. Then they spread out in the area where they laid the letters, making many more marks over a wide area.
“The hummingbird was in a pristine area, untouched,” Mr. Castillo said. “Perhaps it was the best figure.”
Mr. Castillo said that the culture ministry had sent out a team with drone aircraft equipped with cameras so that they could evaluate the damage without entering the delicate area.
He said that the harm was both physical and symbolic.
“This stupidity has co-opted part of the identity of our heritage that will now be forever associated with the scandal of Greenpeace,” he said.
The sign, made of cloth letters, said, “Time for change! The future is renewable. Greenpeace.”
“The impact of climate change is more catastrophic every day,” one of them says to the camera after the sign has been laid out.
In a written statement the group said it was “deeply sorry.”
“We fully understand that this looks bad,” the statement said. “Rather than relay an urgent message of hope and possibility to the leaders gathering at the Lima U.N. climate talks, we came across as careless and crass.”
The group said the stunt took place early Monday and involved activists from Argentina, Austria, Brazil, Chile, Germany and Italy. It said they took the letters with them when they left the area.
The group said it would cooperate with authorities. But on Friday a spokesman in Lima, Mike Townsley, said that the activists involved in the incident had left Peru and that the group had not given their names to government officials.
Annie Leonard, the executive director of Greenpeace in the United States, said the stunt showed “a complete disregard for the culture of Peru and the importance of protecting sacred sites everywhere.” She added, “It is a shame that all of Greenpeace must now bear.”