US Interior Secretary Sally Jewell heads to Africa on Wednesday to denounce the trafficking of wild animals, on the rise over the past five years.

"We are part of the problem, and we want to be part of the solution," Jewell said on the eve of her departure for Gabon.

"Much of the demand is overseas but a lot of it comes to the USA and involves US citizens."

Jewell, who will also visit Kenya and South Africa, said a record number of elephants were killed in Africa between 2011 and 2014.

"Every 15 minutes, an elephant is killed for its ivory," she added, explaining that 100,000 of the animals, including elephant calves, had been killed during that period.

Last year, the conservation chief traveled to Vietnam and China, the world's biggest consumer of ivory, the prized material from animal tusks and teeth.

In order to stress the problem of poaching, a prized source of income for armed groups, US authorities organized in June the destruction of nearly a ton of confiscated ivory objects in New York's heavily-trafficked Times Square in June.

"The only ivory that has value is the ivory that is on a live elephant," Jewell said.

She recalled a disturbing visit to a Colorado warehouse where she saw tiger rugs, coffee tables with elephant feet and others items confiscated by the authorities.

And Jewell also condemned trophy hunting, after a July scandal saw an American dentist kill a prized lion in Zimbabwe.

And there are restrictions on the importation of trophies, for which hunters must sometimes spend hundreds of thousands of dollars.

It is only allowed from "countries that are in fact putting the money... directly into communities to enable those communities support conservation measures for the species," Jewell explained.

Jewell, who spoke with several African officials about animal trafficking during Paris climate talks late last year, is due to continue those discussions with the officials she meets during her upcoming visit.

She will also meet with representatives from non-governmental groups and visit several parks and reserves.