Ruthless and heavily armed "criminal syndicates" linked to drug smugglers and militias are running the global wildlife trade and turning their guns on the park rangers tasked with protecting endangered species.

Hundreds of rangers have been killed over recent years as poachers stop at nothing in their quest for lucrative animal parts such as ivory and rhino horn, according to experts at a global convention on protecting wildlife in Bangkok.

The illegal trade "poses an immediate risk to wildlife and to people, including those serving on the frontlines to protect wildlife" says John Scanlon, secretary general of the Convention on International Trade in Endangered Species (CITES).

"It increasingly involves organised crime syndicates and in some cases rebel militia."

The death toll among the rangers has risen as the slaughter of elephants and rhinos reaches record levels -- with photographs of carcasses stripped of horns or tusks stirring public outcry.

At least 1,000 rangers have been killed in 35 different countries over the last decade, said Sean Willmore, president of the International Ranger Federation (IRF), adding that the real global figure may be between 3-5,000.

"There is an undeclared war going on on the frontline of conservation," he told AFP citing the example of a group of 50 rangers in the Democratic Republic of Congo who stumbled across a 5,000-strong militia group out poaching armed with AK47s.

And while attacks by lions or elephants make their work "dangerous enough", he says 75 percent of the dead were killed by traffickers, with their lack of equipment, training and low wages weighing against them.

Every weakness is exploited by criminals determined to cash in on large animal reserves in some of the world's poorest, most unstable countries.

"Wildlife crime has historically been known as a low-risk, high-profit crime," according to Ben Janse Van Rensburg a senior CITES official.

Alarmingly, the groups are part of a web of global criminals involved in other illicit trades such as drug and human trafficking, he said.

Although the countries worst hit by the scourge of wildlife trafficking have shown willing to tackle the issue, they do so with limited means.

But some countries have not even made the issue a serious crime "making conviction difficult", says Jorge Rios of the UN Office against Drugs and Crime (UNODC), urging political commitment to be "accompanied by resources at national and international level".

For poaching to be curbed those resources must be targeted at a the whole trafficking chain.

"We cannot just focus on poachers... we also have to deal with middle men working in transit countries, and people distributing and selling the merchandise in market countries," Dan Ashe, director of the US Fish and Wildlife service told AFP.

"We have to deal with people who are financing these operations."

But it is not an easy task, with corruption lubricating the movement of illicit wildlife -- often destined for Asia as delicacies or use in traditional medicines.

"They (traffickers) have a lot of money... they are paying for the right to do whatever they want," says Steve Galster, executive director, of conservation group the Freeland Foundation.

After several years of investigation his group accused Vixay Keosavang, an influential Laos national, of orchestrating a major trafficking network.

Tigers, turtles, pangolins, snakes and monkeys from Africa arrived on the banks of the Mekong river in legitimate breeding farms used as a front to sell protected or poached species, he said, highlighting the "loopholes" of CITES that have failed to stop people like him flouting the law.