The global conference that governs wildlife trade voted Monday against strengthening the ban on ivory sales, exposing bitter divisions among African countries and experts over elephant conservation.

The Convention on International Trade in Endangered Species (CITES) rejected a proposal to include all African elephants in its highest category of protection, which bans trade in species facing extinction.

A coalition of 29 African countries -- led by Kenya and Benin -- had pressed for African elephants to be put in the CITES "Appendix I" category.

But South Africa, Namibia and Zimbabwe rejected the proposal, saying they should continue to be excluded from Appendix I as they have stable or growing elephant populations.

"This is a tragedy for elephants," said Kelvin Alie, programme director for the International Fund for Animal Welfare (IFAW).

"At a time when we are seeing such a dramatic increase in the slaughter of elephants for ivory, now was the time for the global community to step up and say 'no more'."

But many experts and delegates at the CITES conference in Johannesburg believed the proposal would have fuelled the illegal market.

- 'Steep decline' -

The proposal to add the four southern African elephant populations to Appendix I could also have led to some countries such as Namibia withdrawing from the CITES treaty, inadvertently opening up "a back door to legal international trade", said Ginette Hemley, head of the WWF delegation.

"African elephants are in steep decline across much of the continent due to poaching for their ivory, and opening up any legal trade in ivory would have complicated efforts to conserve them."

Earlier CITES had voted against proposals by Namibia and Zimbabwe to be allowed to sell off their stockpiles accrued from natural deaths and poaching seizures to fund projects in communities living close to elephants.

"None of these proposals would have offered elephant populations any greater protection from the poachers," Hemley added, urging nations to concentrate on closing domestic ivory markets and combating the illegal international trade.

International trade in ivory has been banned since 1989, but legal domestic markets have continued in some countries, and CITES has allowed sales of African ivory stockpiles to Japan and China in 1999 and 2008.

"We are happy that we have successfully blocked the proposal by Kenya and coalition countries," Zimbabwe environment minister Oppah Muchinguri told AFP.

"It was going to hurt Zimbabwe which has performed so well in growing its own elephant population and ensuring that the proceeds... of any trade was going to be ploughed into the rural people."

A recent census showed a 30 percent decline in the savannah elephant population over seven years, and new data released by wildlife monitor TRAFFIC showed a "rising trend in large raw ivory shipments" last year.

- Sharks protected -

On Monday, the conference voted overwhelmingly to list 13 species of sharks and rays in Appendix II, banning all trade in parts, except under stringent conditions.

Unregulated fishing and international trade in shark products for human consumption have led to a precipitous drop in numbers, with an authoritative 2013 study estimating 100 million sharks are killed every year.

Sharks are also hunted for their meat, skin, liver oil and cartilage, as well as being accidentally caught by industrial "longline" fishing.

Fins are the most valuable part of sharks, with shark fin soup often consumed at prestigious banquets in China, Hong Kong and Singapore.

The CITES conference on Monday also delivered a heavy defeat to a proposal from Swaziland to legalise rhino horn trade.

Some campaigners say that providing a legal supply of farmed rhino horn is the only way to end a sudden boom in poaching of the endangered animal as demand soars in Vietnam and China, where it is mistakenly deemed to have medicinal powers curing everything from hangovers to cancer.

The Johannesburg meeting, which ends on Wednesday, is sifting through 62 proposals to tighten or loosen trade restrictions on around 500 species.

Illegal trade in wildlife is valued at around $20 billion (18 billion euros) a year, according to CITES.

Delegates have already voted to ban all international trade in African grey parrots, one of the world's most trafficked birds, and in the shy, scale-covered pangolin.

The CITES treaty, signed by 182 countries and the European Union, protects about 5,600 animal and 30,000 plant species from over-exploitation through commercial trade.