Huawei, founded by a former People’s Liberation Army engineer, has been largely frozen out of North America despite the company’s insistence that it is independent of the Chinese government. The documents did not reveal whether the American spy agency had found evidence that Huawei was less independent than it claims.

The news reports were published on Saturday by The New York Times and Der Spiegel, and the documents are included in a book by Der Spiegel, “The N.S.A. Complex.”

As with Mr. Snowden’s previous disclosures, the latest revelations about American cyberespionage are likely to complicate efforts by the Obama administration to expose and deter Chinese cyberespionage. Mr. Snowden told a Hong Kong newspaper last year that the spy agency had hacked into Chinese mobile phone companies and network hubs, including computers and servers at Tsinghua University, one of China’s most prestigious schools. Those claims were not independently verified.