BEIJING — Alibaba has a fakes problem.

On Wednesday, American trade officials said they had added Taobao, the Alibaba Group’s sprawling online shopping bazaar in China, to their list of the world’s most notorious markets for counterfeit goods. The addition — an embarrassing setback four years after Alibaba successfully lobbied American officials to drop the platform from the list — comes as the owners of brands increasingly complain about the proliferation of fakes on the company’s sales platforms.

It also comes as Alibaba moves to satisfy increasingly sophisticated Chinese consumers who want higher-quality goods — a shift that has also drawn intensifying competition from Alibaba’s rivals.

Alibaba says it has increased efforts to find and eliminate counterfeit goods. In its report on Wednesday, the Office of the United States Trade Representative acknowledged those efforts — but said they were not enough.

Taobao “is an important concern due to the large volume of allegedly counterfeit and pirated goods available and the challenges right holders experience in removing and preventing illicit sales and offers of such goods,” the agency said, citing complaints from brand owners about the proliferation of fakes on Taobao.