The Justice Department has added new criminal charges against Chinese tech giant Huawei and two of its U.S. subsidiaries, accusing the company in a plot to steal trade secrets, federal prosecutors announced Thursday.

The indictment was announced by prosecutors in Brooklyn who had previously accused the company of bank fraud.

The case was unsealed as the Trump administration is raising national security and surveillance concerns about Huawei, the world's largest telecommunications equipment manufacturer.

Critics, led by Washington, say Huawei is too close to Beijing and its equipment could be used as a tool for spying -- a contention the company strongly rejects.

US President Donald Trump has already ordered American firms to cease doing business with Huawei, and has urged allies to follow suit.

US Attorney General Bill Barr last week said the United States and its allies should take controlling stakes in Nokia, Ericsson or both to battle Huawei's dominance of the 5G market.

Wall Street Journal reported that the Trump administration believes Huawei can covertly access mobile networks around the world through "back doors" designed for use by law enforcement.

It cited US officials saying the company has had this "secret capability" for more than a decade.

The US kept the intelligence highly classified until late last year, when officials provided details to allies including Britain and Germany, the paper said.

However Huawei vehemently denied the report, saying in a statement it "has never and will never covertly access telecom networks, nor do we have the capability to do so."

It said that even the WSJ conceded US officials "are unable to provide any concrete details concerning these so-called 'back doors'."