The Swiss-based World Conservation Union (IUCN) has called for greatly increased international action in the face of growing threats around the world to endangered species.
In its latest Red List of Threatened Species, published on Thursday, the IUCN says that 24 per cent of mammals and 12 per cent of birds are threatened with extinction.
It adds that more than 11,000 plants could also disappear in the near future.
From its headquarters at Gland, near Geneva, the IUCN said that since the last assessment in 1996, critically endangered primates had increased from 13 to 19 and the number of threatened albatross species had risen from three to 16, due to long-line fisheries.
Freshwater turtles, heavily exploited for food and medicinal purposes in Asia, went from 10 to 24 critically endangered species in just four years.
The release of the Red List comes a week before the second World Conservation Congress in the Jordanian capital, Amman, where members of the IUCN will meet to define global conservation policy for the next four years, including ways of addressing the growing extinction crisis.
The IUCN's Swiss director general, Maritta von Bieberstein Koch-Weser, says that the fact the number of critically endangered species has increased was a "jolting surprise" even to those familiar with today's increasing threats to biodiversity.
"These findings should be taken very seriously by the global community," she says.
The President of Conservation, Russell A. Mittermeier, said that the Red List was solid documentation of the global extinction crisis and it revealed "just the tip of the iceberg".
"Many wonderful creatures will be lost in the first few decades of the 21st century unless we greatly increase levels of support, involvement and commitment to conservation," he said.
The Red List report says that human and financial urges human and financial resources to be mobilised between 10 and 100 times the current level to address the crisis.
swissinfo with agencies
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