Lions walk in the Ngorongoro Crater in Ngorongoro Conservation Area, west of Arusha, northern Tanzania, Monday, Jan. 19, 2015. Mosa'ab Elshamy/AP hide caption

toggle caption

Mosa'ab Elshamy/AP

Ten lions found dead in a wildlife reserve in Tanzania are suspected to have been poisoned, according to wildlife officials. The animals were discovered on Friday in the Ngorongoro Conservation Area, home to pastoral tribal communities that raise cattle. It is also one of the most visited tourist destinations in the country.

"Preliminary findings suggest the animals may have died after ingesting poison," a statement from The Ngorongoro Conservation Area Authority said, adding the authority has launched a full investigation "to determine the cause of the incident and identify those responsible."

Large animals are under threat across East Africa, in places where they frequently come into conflict with humans. An investigation is underway in neighboring Kenya, where over the summer, 18 elephants died from suspected poisoning. Police have arrested four people.

According to Kenya's Wildlife Service, preliminary tests showed the elephants may have ingested cyanide. Tomato farmers in the Amboseli region are known to use banned pesticides on their crops. But growers deny using cyanide.

Tanzania is home to Africa's largest lion population, about half the world's wild lions. But they are listed as a vulnerable population by the International Union for Conservation of Nature. Lions are under threat from shrinking habitat and poaching.

The Ngorongoro Conservation Area in Tanzania is a UNESCO World Heritage Site protected under international law. It is the location of the Ngorongoro Crater and home to the Big Five game animals -–the elephant, lion, leopard, buffalo and rhino.