Dar es Salaam, Tanzania ? Rocks and boulders tumbled down Mount Kilimanjaro on Wednesday and crashed into a group of climbers sleeping in tents before their final ascent of Africa’s highest mountain. Three foreign climbers and an unknown number of guides were killed.

A sudden change in weather at Kibo peak dislodged the rocks, Tanzania National Parks head Gerald Digurube said. He said five foreigners were seriously injured and were taken to Kilimanjaro Medical Center for treatment.

Thomas Kimaro, owner of Alpine Tours, a Tanzanian company that organizes trips to Kilimanjaro, said several Tanzanian guides were among those killed and injured, but he could not say how many.

No information was immediately available on the nationalities or names of the foreign climbers.