Wildlife rangers killed an armed poacher in a shootout after he and others infiltrated a private ranch and shot dead an elephant, Kenya Wildlife Service said Tuesday.

A rifle and bullets were recovered at the scene of the shootout in Choke Ranch in Kenya's south, and the surviving poachers fled before they could cut off the elephant tusks, the service said.

Human rights groups have accused wildlife rangers of executing suspects. A report released by the Muslims for Human Rights group last year accused some rangers of executing suspected poachers to cover their involvement with them.

The years 2011, 2012 and 2013 witnessed the highest levels of poaching since a poaching crisis in the 1980s, the service said.

Poaching declined last year with 164 elephants and 35 rhinos killed, down from 302 elephants and 59 rhinos killed in 2013. Officials attributed the decline partially to stiffer penalties adopted last year for those involved in the illegal wildlife business.

Separately, Chinese national Gao Xudong, 61, was arrested for allegedly trying to smuggle nine kilograms (20 pounds) of ivory while travelling from Kenya to Hong Kong, the service said.

Xudong will be charged with being in illegal possession and dealing with a wildlife trophy, both which have a maximum sentence of life in prison or a fine of $22,000, spokesman Paul Gathitu said.

Wildlife activists say illegal ivory smuggling in Africa increased after the 2007 temporary lifting of a ban by the Convention on International Trade in Endangered Species. It allowed a one-off sale by African countries that had stockpiles of ivory from elephants that had died naturally or problem elephants killed by wildlife officials.

Poaching deaths of elephants to meet demand for ivory in China is an escalating crisis across Africa. A report last year by Africa's leading elephant experts, including Save the Elephants, estimated that poachers killed 100,000 elephants between 2010 and 2012 on the continent.

Kenya's elephants are an important tourist draw and fall in the category of star wildlife attractions in the country known as the big five. The other four are leopards, lions, rhinos and buffalo.