WASHINGTON — Huawei has the ability to secretly retrieve sensitive information in next-generation wireless networks and other systems it maintains around the world, a top White House official said Tuesday.

The comment from Robert C. O’Brien, the national security adviser, is one of the sharpest public denunciations of the Chinese company by the Trump administration, and comes as the United States is reeling from the decision by Britain to allow Huawei to build part of their fifth-generation, or 5G, network.

American intelligence officials have long said privately that Huawei has so-called back doors that could allow the company to obtain data that flows on the networks they build and maintain. But publicly, officials have spoken mostly about the potential that Huawei could provide Chinese officials with access to all kinds of data, without offering concrete proof.

Mr. O’Brien said Tuesday that the United States had evidence that Huawei could “access sensitive and personal information” in the systems it maintains around the world.