By Jonathan Head
BBC News, Bangkok
Conservationists say much of the demand for ivory originates in China
The illegal ivory trade in Vietnam is threatening the survival of South East Asia's dwindling elephant population, a wildlife monitoring organisation says.
Ivory prices in Vietnam are higher than anywhere else in the world, indicating rising demand, researchers from the international group, Traffic, found.
Around 4,000 tonnes of illegal wildlife products are estimated to pass through Vietnam every year.
There are thought to be fewer than 150 elephants left in the wild in Vietnam.
The trade in ivory was officially banned in Vietnam 16 years ago - but because of a loophole in the law allowing shops to sell tusks obtained before that year, the trade still carries on.
Traffic, the international organisation that monitors the wildlife trade, believes the ivory business could be growing again in Vietnam, after a survey showed prices were higher there than anywhere else in the world.
Tonnes of illegal wildlife products are estimated to pass through Vietnam every year - and the source of these products remains a cause of acute concern to conservationists.
A combination of decades of war, followed by rapid economic and population growth, has degraded many of Vietnam's own forests.
But in Laos, the communist state next door, which has long been under the sway of its more powerful neighbours, there are still extensive forests, with perhaps 1,000 elephants living wild.
These forests and their inhabitants are being plundered at an alarming rate, say conservation groups, to feed demand in Vietnam and China.
A recent study by the WWF found more than 1,000 new species of animal in this region, evidence of its rich biodiversity.
Traffic is asking the Vietnamese government to improve what it describes as erratic monitoring of illegal elephant products, and to close the legal loopholes that allow the ivory trade to continue.