Ancient cave paintings at a world heritage site in the Sahara desert have been defaced with graffiti, Chad's minister of culture has told the BBC.
The graffiti drawn on the paintings, which are about 8,000 years old, was "a tragedy... offensive to the whole history and memory of Chad," Mahamat Saleh Haroun said.
Vandals scrawled their names on top of the artworks in French and Arabic.
The Ennedi plateau was declared a Unesco world heritage site in 2016.
"It's an African story and they wanted to destroy that.
"That's why I'm talking about a tragedy, because it's a part of us," said Mr Haroun, who is also an award-winning filmmaker.
Local youths are suspected of being behind the vandalism.
A team has now been sent to the site in north-eastern Chad to assess the damage, with a view to sending experts to follow up.
The head of the UN's cultural body in the country, Abdelkerim Adoum Bahar, told the BBC that he thought the damage could be repaired.
Thousands of images of people and animals have been painted and carved into the rock surface of caves, canyons and shelters in the area, according to UN cultural agency Unesco.
Mr Haroun stressed the historical importance of the site, which he said belonged not just to Chad but to the whole world.
"This is a part of our memory. It helps us to understand who we are... We cannot destroy it. If you don't know your past you cannot deal with the present," he said.