A large boulder that fell on the road and blocked buses from reaching the Inca fortress of Machu Picchu forced visitors to travel the final 2 kilometers (1.2 miles) on foot, Peru's National Police said.

"Situations like this are caused by the weather, but we're working to guarantee the safety of visitors and locals," police Maj. Juvenal Cereceda told Canal N television.

The boulder was 7 meters (23 feet) wide by 5 meters (16 feet) high, and had been loosened by the Cuzco region's heavy rains, causing it to fall, authorities said.

Local officials said that work to open the road again is being done with special machinery so as not to damage the route nor the historic site's surroundings.

Cereceda said the railroad company Peru Rail also suspended its trips during the day to avoid buildups of traffic in the area, since Machu Picchu receives some 2,500 visitor a day.

This week, representatives of the Culture Ministry and directors of the Inca fortress announced that next year they plan to change the place of exit from Machu Picchu, to avoid buildups of crowds and traffic all at the same place, though this measure is still being studied. EFE