A medical evacuation plane operated by AMREF Flying Doctors crashed Thursday in a residential neighborhood near Nairobi, Kenya, killing at least six people, according to local officials and the company.

Kiambu County Commissioner Henry Wafula said six people on the plane were killed, including doctors, nurses and the pilot - as well as another two people on the ground, while two others were seriously injured. Investigators have been despatched to the scene of the crash to establish its cause.

Four people were killed Tuesday when a medical transport plane crashed on Navajo Nation land in Arizona, according to tribal police.