At least 22,000 African elephants are estimated to have been killed in illegal hunts for their ivory in 2012, and the figure is expected to have stayed at the same level in 2013, according to the secretariat of the Washington Convention.
It is calling on China, Japan and other Asian countries, the major destinations for ivory, to enhance their systems to prevent unlawful imports given concerns over the extinction of African elephants in many parts of the continent.
The number of illegally hunted African elephants annually accounts for 7.4 percent of their overall population in the geographical areas of the study.
As their basic reproductive ratio is 5 percent at the highest, uncontrolled illegal hunts are certain to cause a decrease in the population, according to the secretariat of the Convention on International Trade in Endangered Species of Wild Fauna and Flora and the International Union for Conservation of Nature and Natural Resources.
The amount of seized illegal ivory has been rapidly increasing since around 2009, reaching 41,674 kilograms in total last year, the most in the past five years.
While Japan was one of the main destinations of illegal ivory until around 2008, imports have fallen recently. Instead, illegal ivory is heading to China via Southeast Asian nations.