Yahoo Japan Corp. said on Wednesday it will end the sale of ivory on the country's biggest online auction site, finally joining competitors in a ban.

Yahoo Japan will end ivory trading, blamed by wildlife campaigners for perpetuating an illegal international black market, from Nov. 1, the company said in a statement, confirming an earlier Reuters report.

Rival e-commerce firms Rakuten Inc. and Mercari Inc. banned ivory sales two years ago, but Yahoo Japan had continued to resist calls from campaigners, denying suggestions the trade was a factor behind a sharp rise in poaching on the African savannah in recent years.

Elephant tusks remain in demand in Japan, which allows the domestic trading of ivory brought into the country before it imposed an import ban in 1989, making it the world's largest legal ivory market.

The tusks are used to make "hanko" name seals which, when dipped in red ink and stamped on paper, are used like a signature in a wide range of transactions from opening a bank account to registering a marriage.

Yahoo Japan, a consolidated subsidiary of telco SoftBank Corp., said it decided to halt trading following reports that ivory bought on Yahoo Japan's platform was taken overseas illegally. Two sources told Reuters the reports were regarding on-selling to China.

China outlawed the trade in 2017, with increasingly strict rules around the world another factor behind the decision, the sources said.

A report by wildlife trade monitoring group Traffic last year pointed to seizures of Japan-procured ivory being smuggled into China. Ivory transactions on Yahoo Japan's auction site totaled around 40 million yen ($380,000) over a four-week period in May and June last year, Traffic estimated.

The Japanese government last month began requiring domestic traders to prove the age of tusks via carbon dating in a bid to prevent illegal imports.

An estimated 100 African elephants are killed each day by poachers seeking ivory, meat and body parts, leaving only 400,000 remaining, environmentalists estimate.