Peru says it has formally warned a prestigious U.S. university that the government will sue if artifacts taken from Machu Picchu are not returned.
Peru's Foreign Ministry said in a statement on the ministry's Web site the president of Yale University has been told the nation will pursue a lawsuit if necessary, although a settlement is preferred.
Peru is demanding the return of nearly 5,000 objects an American explorer removed from Machu Picchu during a series of expeditions almost a century ago.
Peru's National Institute of Culture says the treasures were loaned to Yale University, but they were to be returned to Peru in 1916.
The ancient city of Machu Picchu is perched on a ridge more than 2,500 meters up in the Andes Mountains. The city is considered an archeological gem and a marvelous display of the Incas' construction techniques.
The city is a major tourist attraction, visited by about 300,000 people each year.
Some information for this report provided by AP and Reuters.