Laws designed to stop species from becoming extinct because of the international trade in them are to be discussed at a global summit in Chile.

Some of the agreements under the Convention on International Trade in Endangered Species (Cites) could be tightened while there is pressure to relax others, correspondents say.

Lobby groups are to push for tougher action against illegal mahogany logging

The survival of dozens of species of plants and animals are set to be discussed at the summit in Santiago by about 2,000 delegates from the convention's 160 member countries.

African elephants, Asian turtles and American mahogany trees are among the items on the agenda.

The debate over some resumption in the trade of ivory from elephants is set to be one of the most emotional issues at the conference.

Five African countries want permission to sell a proportion of their existing stocks, and put the income towards elephant conservation.

But India and Kenya argue that any ivory sales could pose a future threat to the African elephant.

'Success story'

Cites is one of the largest conservation agreements in the world and its organisers say it is very successful.

The group says that since Cites was established 27 years ago, not one species it has listed for protection has become extinct as a result of trade.

Black bears in China have open wounds from which bile is "milked"

But a BBC science correspondent, Helen Sewell, said its rules were often broken, such as in the case of Asiatic black bears, brown bears and sun bears - protected under the treaty - which are "milked" for their bile which is used in Chinese traditional medicine.

The World Society for the Protection of Animals says thousands of bears are purposely wounded to provide the bile and it claims the practice is hastening the demise of the three species.

It will be lobbying for greater protection for the bears to be agreed in Santiago while the World Wildlife Fund (WWF) wants better measures for elephants as well as the big cats of Asia, and the highly prized mahogany trees of Mexico, Central and South America.

Other issues likely to be raised at the meeting include more protection for:

• Patagonian toothfish - which face pirate fishing in southern oceans
• Whale sharks - the largest fish in the sea which are traded for meat, fins and liver oil
• Hawksbill turtles - illegally traded for their tortoiseshell
• Seahorses - caught in vast quantities for traditional medicine and aquaria

The meeting of Cites - run under the auspices of the United Nations Environment Programme - is scheduled to last for 12 days.