Story highlights Environmental group claims Chinese delegation went on an ivory buying spree in Tanzania

It cites local traders saying the ivory was sent back to China on the presidential plane

China's government has not responded to CNN requests for comment on the claims

Tanzania lost equivalent of 30 elephants a day in 2013, environmental group says

Chinese officials who accompanied Chinese President Xi Jinping on a visit to Tanzania last year went on a buying spree for illegal elephant ivory, an environmental activist group has claimed.

The report by the Environmental Investigation Agency cites two local ivory traders as saying that the large Chinese government and business delegation bought so much ivory while in the country that prices doubled.

The two traders claimed that a fortnight before the state visit, Chinese buyers began purchasing thousands of kilos of ivory, the report says.

That ivory was later sent to China in diplomatic bags on the presidential plane, the dealers said, according to the report.

One of the traders, named as Suleiman Mochiwa, told an undercover investigator for the EIA in September, "The price was very high because the demand was high. When the guest come, the whole delegation, that's then time when the business goes up."

He said the price of ivory doubled during the Chinese visit to $700 per kilo.

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The second trader, named as Paulo Gavana, gave the same account.

Groundless

Chinese authorities were less than impressed by the report.

"The report is groundless, and we express our strong dissatisfaction," said Hong Lei, China's Foreign Ministry spokesman, at a press briefing on Thursday.

"We attach importance to the protection of wild animals like elephants. We have been cooperating with other countries in this area."

The sales were made by dealers operating out of the Mwenge Carvers Market in Dar es Salaam, the EIA claims.

Another Mwenge dealer who spoke to undercover reporters in 2010 made similar claims about the entourage that accompanied past Chinese President Hu Jintao to Tanzania in 2009, the report said.

He is quoted as saying: "You know when the President of China, Hu Jintao, was coming to Tanzania? They come to take many things. But that was not for Hu Jintao, it was the whole group. Then they go direct to the airport, because VIP no-one checks your bags."

Slaughtered en masse

The report adds that going back as 2006, EIA investigators were told by Mwenge suppliers that Chinese Embassy staff were the major buyers of their ivory.

The EIA report highlights the threat posed to Tanzania's elephant population by illegal poaching -- and warns that they are being "slaughtered en masse" to satisfy a growing demand for ivory.

"Based on available evidence, Tanzania has lost more elephants to poaching during this period than any other country. In 2013 alone, it reportedly lost 10,000 elephants, equivalent to 30 a day," it says.

"Tanzania's elephants continue to be poached to supply a growing demand in an unregulated illegal ivory market, predominantly in China."