Nairobi — Britain's Prince William has mourned wildlife reservist Mark Jenkine and his son who died in a plane crash at the Tsavo East National Park.

Taking to his social media, William expressed his grief and stated that he had a long-standing friendship with Jenkins following the tragedy.

"Yesterday, I lost a friend, who dedicated his life to protecting wildlife in some of East Africa's most renowned national parks. Mark Jenkins, and his son Peter, were tragically killed when flying over Tsavo National Park while conducting an aerial patrol," he wrote on Twitter.

"Tonight, I'm thinking about Mark's wife, family and colleagues who've sadly lost a man we all loved and admired."

Jenkins, a wildlife ranger and his son Peter (a game warden) lost their lives after their aircraft crashed on Thursday morning while on patrol in the park's north-eastern boundary.

William's friendship with Jenkins dates back to 2001 when he visited the continent for a three-year period where he learnt about game conservation, wildlife and its environment.

They were trying to drive cattle that included cows, camel and goats out of the park when the incident happened.

Officials said they are investigating claims the plane may have been shot from the ground.

But another official added it was too early to know the cause of the crash.

The area has been invaded by herders with their animals for pasture. This has caused conflict between authorities and the herders.

Coast regional police officer Titus Karuri said experts are investigating the accident.