About 150 tigers are killed each year by poachers — 5 percent of the world's wild tiger population, Yuri Fedotov, head of the U.N. office on drugs and crime, told participants at a summit meant to address the animal's rapid population decline.

He said tiger poaching brings $5 million in profits.

"Often, crimes against wildlife are related to money laundering, violence, and in some cases could even be tied to terrorism," Fedotov said. "Only our common operations will help stop the trade."

Yelena Averyanova of the International Fund for Animal Welfare said up to 50 Siberian tigers are killed annually in Russia's Far East to be sold in China. Their pelts, bones and meat are prized in traditional Chinese medicine.

Tigers once roamed most of Eurasia from the Tigris River to Siberia and Indonesia. But in the past century, the number of countries that are home to tigers has dropped to 13 from 25, while three of the nine tiger subspecies have become extinct. The World Wildlife Fund and other experts say only about 3,200 tigers remain in the wild, a dramatic plunge from an estimated 100,000 a century ago

Russia is among the 13 countries with remaining tiger populations, and the St. Petersburg summit is hosted by Russian Prime Minister Vladimir Putin. He has bolstered his image by posing with a cuddly cub and placing a tracking collar on a full-grown female in the country's Far East.

The summit, which runs through Wednesday, has already approved a wide-ranging program with the goal of doubling the world's tiger population in the wild by 2022.

Up to 50 Siberian tigers are killed annually in Russia's Far East to be sold in China, said Yelena Averyanova of the International Fund for Animal Welfare. Their pelts, bones and meat are prized in traditional Chinese medicine, and each tiger costs up to $50,000, she said.

Poachers come up with increasingly cruel methods of catching and killing their prey such as attaching explosives covered with animal fat to tree branches, she said. When tigers swallow the bait, it explodes in their mouths, she said.

Much has been done recently to try to save tigers, but conservation groups say their numbers and habitats have continued to fall, by 40 percent in the past decade alone.

The Global Tiger Recovery Program estimates the countries will need about $350 million in outside funding in the first five years of the 12-year plan. The summit will be seeking donor commitments to help governments finance conservation measures.

Maria Otero, the U.S. State Department undersecretary for democracy and global affairs, said Washington "was committed to stop the illegal trade for every species", including tigers.

The United States finances many programs on saving tigers, including ones in Asia, Russia and China, she said.

Tigers occupy the top of the ecological system in vast forest landscapes, and their existence depends on diverse and undisturbed habitats.

Economic development and limited capacity for conservation efforts have contributed to degradation and fragmentation of the habitats and depletion of prey animals.