A head-on collision between two trains on the line that services Peru's Machu Picchu killed one person and injured at least 40 others, authorities said.

The deceased was the conductor of one of the two trains, according to the prosecutor's office in Cusco, the city closest to the famous Inca citadel.

The U.S. Embassy in Peru said in a statement that there were U.S. citizens among the injured. It did not indicate how many Americans were hurt or the extent of their injuries.

Videos sent by passengers to the RPP television channel showed injured victims lying next to the tracks with two damaged locomotives standing idle nearby.

A dozen ambulances and medical personnel were rushed to the site in a remote Andean area without direct road access.

A UNESCO World Heritage Site since 1983, the ancient, fortified complex receives some 4,500 visitors on average each day, many of them foreigners, according to the tourism ministry.

Most tourists take a train and a bus to reach the historic site high in the Andes mountains.

Rail agency Ferrocarril Transandino said a train operated by PeruRail collided with another belonging to Inca Rail around lunchtime on the single track that links the town of Ollantaytambo with Machu Picchu. The cause of the accident was not yet known.

Machu Picchu was built in the 15th century at an altitude of about 8,200 feet on orders from the Inca ruler Pachacutec. It is considered a marvel of architecture and engineering.