Conservationists said Friday the number of elephants in a national park in eastern Congo has increased during the last three years, despite continuing poaching and fighting. But the cost of protecting the animals has been high, with 100 rangers being killed there in the last decade.

Virunga National Park is Africa's oldest, and it once boasted the highest density of large mammals in the world.

However, during the last decade, the park, which lies on the Democratic Republic of Congo's eastern border, has also been turned into a battleground, where national armies and rebel groups have fought each other and plundered what they saw.

As a result of the unrest, poaching became rampant and the populations of elephants, buffalo and other large animals fell dramatically.

But a recent survey by conservationists working in Congo's lawless east has found that conservation efforts are paying off, and these populations are now increasing.

There are now about 340 elephants, whereas, three years ago, there were just 265, the Wildlife Conservation Society and Congo's Nature Conservation Institute said in a statement Friday.

Populations of buffalo and Ugandan kob have also been on the rise, the conservationists said, after the survey was carried out earlier this month.

Protecting animals in a country that has had two wars during the last decade has come at a cost, however. Over 100 of Virunga's park rangers have been killed on the job during the same period.

Next month, Congo is due to hold its first free and fair elections in over 40 years. And conservationists hope that by protecting the country's animals during the time of war, they will be able to attract tourists during the peace.