( CNN ) -- Kenyan park rangers are hunting for a gang of poachers who they say killed eleven elephants and hacked off their tusks , the latest large slaughter of the animals to be reported amid insatiable global demand for ivory . The family of elephants were killed on Saturday in Tsavo East National Park in southern Kenya , according to a statement Monday from the Kenya Wildlife Service . The animals ' carcasses all had bullet wounds and their tusks had been chopped off , the agency said . Read more : African ivory worth $ 1.4 million seized in HK . Teams of rangers on foot and in the air are trying to track down the poachers in the 22,000-square-kilometer ( 8,500-square-mile ) park , the country 's largest single ecosystem , according to the wildlife service . It said it believed around 10 poachers were involved . The killing follows warnings last year from conservation groups that elephants were being slaughtered in Africa at an alarming rate to feed demand for ivory from increasingly affluent Asian countries , particularly China and Thailand . At the same time , the groups said , poachers are becoming more heavily armed , making it harder for often ill-equipped park wardens to protect the animals . Read more : How Nanibia turned poachers into gamekeepers . In an indication of the amount of illegal ivory in circulation , authorities in the Asian port of Hong Kong have announced three major seizures of smuggled shipments since October . They confiscated 779 pieces of tusk , worth the equivalent of about $ 1.4 million , last week . The Tsavo park , a protected area , is home to an estimated 13,000 elephants , based on a census in 2011 , Kenya Wildlife Service said . A representative of the agency was n't immediately available to comment Tuesday on the latest developments in the pursuit of the poachers . CNN 's David McKenzie reported from Johannesburg , South Africa , and Jethro Mullen reported and wrote from Hong Kong .
The killing took place in Tasvo East National Park in southern Kenya . Rangers say they are pursuing the poachers with ground and aerial units . A Kenyan official says that a group of men armed with machetes attacked rangers at an entrance to the park on Saturday, leaving one ranger dead.