SHANGHAI, China — Alibaba Group Holding Ltd's chief Jack Ma has cancelled a planned speech at an anti-counterfeiting conference in the United States after the trade group behind it suspended the e-commerce giant's recently gained membership.

Alibaba has been dogged for years by accusations that its online shopping platforms were conduits for counterfeiters and critics say it has not done nearly enough to stop the problem.

At least three members of the Washington-based International Anti Counterfeiting Coalition, including board member Tiffany & Co., quit the group and others threatened to leave in protest after Alibaba was admitted as a member in April.

On Friday, the IACC suspended the new category in which Alibaba was admitted, effectively terminating its membership.

"Given the IACC's desire for additional time to reflect upon the viability of its general membership category, Alibaba feels it best that Jack Ma postpone his appearance," Jennifer Kuperman, head of international corporate communications, said in a statement.

Alibaba Group President Michael Evans will speak at the conference in Orlando, Florida instead.

Kuperman reiterated Alibaba's stance that it is "firmly committed to the protection of intellectual property rights and combating counterfeits."

Damaging Adversary

China's biggest e-commerce firm has pledged to fight fake goods and has hired an army of employees to root them out, but many brands say the problem is still widespread, particularly on the hugely popular shopping site Taobao.

In a letter to the IACC explaining its decision to leave the group, luxury brand Michael Kors called Alibaba "the largest marketplace for counterfeit merchandise the world has ever seen" and blasted the IACC for providing "cover to our most dangerous and damaging adversary."

Gucci, Yves Saint Laurent and other brands held by Paris-based Kering SA filed a suit in New York in May last year alleging that Alibaba had knowingly made it possible to sell fake products.

Last week Taobao said it was tightening controls on the sale of luxury goods, requiring sellers to show proof of authenticity as a way to try to combat the sale of fakes.

Fake products, ranging from Beats headphones to infant milk formula, are widespread in China — both online and in bricks-and-mortar shops.

The official People's Daily newspaper said this month Chinese authorities would launch a campaign to clean up e-commerce, targeting trademark violations, counterfeit and poor quality products, in a move potentially affecting Alibaba as well as rivals JD.com Inc and Baidu Inc.

By John Ruwitch and Aurindom Mukherjee; editors Tom Brown and Edwina Gibbs.