Kenya's proposal to introduce a 20-year moratorium on the ivory trade has been rejected at a meeting in Bangkok.
Africa is currently home to an estimated 400,000 to 660,000 elephants
The idea did not get the votes needed for approval at the biennial summit of the Convention on International Trade in Endangered Species (Cites).
The Thai gathering also turned down a request from Namibia for an annual export quota of two tonnes of ivory.
But delegates did back a continent-wide plan by African nations to crack down on domestic, unregulated ivory markets.
Countries with these home markets will now either strictly control their trade or prevent it completely.
The nations will create and implement legislation to improve law enforcement and border controls. They will also update Cites on their progress early next year.
An international ban on the trade in elephant ivory - used for decorative carvings and jewellery - was agreed in 1989 after years of poaching had seen African populations plummet.
Today, there are estimated to be 400,000 to 660,000 elephants on the continent.
Kenya, which was hit hard by poachers in the 1970s and 80s, shortened the length of its proposed moratorium during the meeting.
As discussions continued throughout Monday, the initial 20-year ban was reduced to six years.
At one stage, the EU recommended the adoption of an unspecified period - but this, too, could not gather the two-thirds majority required to be passed.
DEGREES OF PROTECTION
Appendix I: controls species whose existence is so threatened that trade is banned. Covers some 1,000 plants and animals, eg great apes
Appendix II: Allows controlled trade, under a system of permits. Covers 4,100 animal species and 28,000 plants
Appendix III: Contains 290 species that are protected in at least one country.
"Those who voted against this proposal have voted against elephants. In a few years' time, some elephant populations, particularly in central and west Africa may disappear forever," said Peter Pueschel, head of the International Fund for Animal Welfare's Cites delegation.
"The proposal was absolutely vital to give all nations time to be more successful in their efforts to stop poaching and to address other enforcement issues to bring an end to the illegal trade in ivory."
But the call for an extended moratorium had highlighted the sharp divisions that exist between some nations on the best way to conserve elephants - between those, like Botswana, who believe the animals' value can be used to fund better protection; and those, like Kenya, who feel a freer trade would be exploited by poaching.
Reservations were expressed at the summit about the practicality of such a long ban.
Namibia had wanted the two-tonne sales to fund its elephant conservation projects.
"Without a way of benefiting from elephants, elephants are regarded as a liability and economic cost to rural communities, who suffer crop losses, other damages and lose human lives to elephants," its proposal had read.
Jaques Berney, executive vice-president of IWMC, a group which campaigns for the sustainable use of wildlife, criticised the decision to deny the Namibian sales: "The case in favour of this trade was clear. It would have aided elephant conservation, helped local communities and complemented existing management programmes.
"Unfortunately, Cites has sent a negative signal to poor rural communities in Namibia, who are now being told that they must wait for the completion of bureaucratic processes outside their control before they can use their limited resources to support their families."
In a separate move, however, Namibia was given permission to trade in elephant leather and hair goods for commercial purposes. A South African proposal to trade in elephant leather commercially was also approved.
The Cites meeting runs until Thursday. It has already agreed to ban sales of the rare Irrawaddy dolphin, whose numbers are thought to be as low as 1,000 in the wild; and has approved trophy exports of a small number of African black rhinos.
On rare plants, it has tightened controls on the trade in ramin wood. The ramin is a large tropical hardwood tree found in the peat swamp forests of Indonesia and Malaysia, which are also home to the world's last remaining orang-utans.
Already listed in Appendix III of the convention, ramin was elevated to Appendix II by delegates.
Monday saw the 10 member countries of the Association of Southeast Asian Nations (Asean) announce a programme to better co-ordinate their efforts to fight illegal wildlife sales.
The region is seen as a major world hub for the multibillion dollar trade because of weak laws and poor enforcement.
Asean states will share intelligence and scientific data on threatened species, among other measures.