In 2006 there were only 350 elephants in Virunga National Park
Fourteen rare elephants in the Democratic Republic of Congo's Virunga National Park have been killed since mid-April, a conservation group says.
A 2006 survey showed there were only 350 elephants in the war-ravaged park, a Unesco World Heritage Site.
"We've been taken by surprise by the intensity of the killings," Emmanuel de Merode of WildlifeDirect told the BBC.
He said that he feared it may be linked to South Africa's decision to lift a 13-year moratorium on elephant culling.
"All 14 were killed by automatic rifle; they were cut up for their meat and with the exception of the final one, their ivory was taken away," Mr Merode told the BBC's Network Africa programme.
Four poachers were caught after the last incident by a joint patrol of Congolese military and park rangers, he said.
"We believe it may be linked to factors outside Congo that relate to the reopening of the ivory trade."
South Africa's government halted the killing of elephants in 1995 but since then numbers have more than doubled and it now needs to control the numbers.
But Mr Merode said that South Africa could now also trade its ivory.
"Unfortunately this has huge impact on rest of Africa, with the reopening of a legal ivory trade - illegal ivory can very easily be sold on the market," he said.
A five-year conflict in DR Congo officially ended in 2003, but several militia groups still operate in the park, which stretches 8,000 sq km along DR Congo's border with Rwanda and Uganda.
Since 1996, 120 rangers have been killed trying to protect the park's wildlife.
Last year, rebels killed five rare mountain gorillas in the park.
Congolese conservationists estimate there was population of 70,000 elephants before the war.
South Africa lifts its culling ban