Two suspected poachers have been arrested in Kenya over the killing of five elephants in Tsavo National Park, wildlife authorities said Wednesday.

The Kenya Wildlife Service said a major manhunt was in progress to catch the rest of the poaching gang following the discovery of the bodies of a female adult and four young adult elephants, all with their tusks missing.

The killings took place in Tsavo West National Park, which borders Tanzania. The park is Kenya's main elephant sanctuary and home to some 11,000 pachyderms.

"The suspected gang is believed to comprise of four Tanzanians who operate across the Tanzania-Kenya border assisted by some Kenyans from the local area. They are believed to have used motorbikes to escape with the tusks," the KWS said.

The wildlife service estimates Kenya's elephant population at 38,000 nationwide, but hundreds are being lost to poaching every year -- and conservationist have warned that African elephants could be extinct in the wild within a generation. Ivory rakes in thousands of dollars a kilo in Asia.