Nairobi, Kenya (CNN) -- A plane crash in Kenya on Wednesday killed four people, emergency workers said.
The crash occurred in the country's Maasai Mara national park, said Sean Culligan, chief operations officer for Flying Doctors, which is assisting in the response.
Two Kenyan pilots and two Germans were killed, according to emergency workers.
In Washington, a State Department spokeswoman said Americans also were on the plane.
"We can confirm that four U.S. citizens were injured in a plane crash today in Kenya," Laura Seal said.
"Officials from the U.S. Embassy in Nairobi are providing appropriate consular assistance. Due to privacy considerations, we cannot provide further details."
Flying Doctors is a Nairobi-based charity that evacuates people from medical emergencies in East Africa and does air ambulance transfers between medical facilities.
It also flies doctors to remote areas to provide health care. The charity has been operating since 1957.
CNN's Jamie Crawford contributed to this report.