The Department of Justice has announced new criminal charges against Huawei, accusing the Chinese tech giant of being engaged in a 'decades-long' effort to steal trade secrets from a slew of US companies.

The 16-count superseding indictment unsealed on Thursday adds RICO charges to the criminal case against Huawei and its CFO Meng Wanzhoua, who is currently fighting extradition in Canada.

The charges come in addition to previous criminal charges accusing Huawei and Wanzhoua of operating a secret subsidiary in Iran and lying to U.S. financial institutions about the violation of sanctions on that country.

The new charges detail a brazen decades-long scheme to steal trade secrets from at least six U.S. companies. Cisco and T-Mobile are among the alleged victims in the case, though the companies are not actually named in the new indictment.

Huawei CEO Ren Zhengfei is seen with Chinese President Xi Jinping in 2015. US officials accuse the company of building a secret back door into its mobile network hardware

The new indictment alleges Huawei and two of its US subsidiaries - Huawei USA and Futurewei - 'conspired to violate the Racketeer Influenced and Corrupt Organizations Act (RICO)' by stealing trade secrets.

Prosecutors say that in 2013, Huawei instituted a cash bounty program 'to reward employees who obtained confidential information from competitors' and that the more valuable the secrets were, the more the company paid out.

The indictment details a shocking incident from 2004, at a trade show in Chicago, where prosecutors say a Huawei employee was busted in the middle of the night while breaking into a competitor's booth.

The employee was wearing a bogus badge identifying him as an employee of 'Weihua', which is the syllables of Huawei reversed, and was caught taking pictures of the interior circuit boards of a competitor's product, according to the indictment.

A Huawei spokesman denied the allegations, saying that the indictment was 'part of an attempt to irrevocably damage Huawei's reputation and its business for reasons related to competition rather than law enforcement.'

The company called the racketeering accusation 'nothing more than a contrived repackaging of a handful of civil allegations that are almost 20 years old.'

Huawei pleaded not guilty to the earlier indictment unsealed against the company in January 2019, which charged it with bank and wire fraud, violating sanctions against Iran, and obstructing justice.

Wanzhoua, the CFO, was arrested in December 2018 in Canada on charges in the prior indictment, but she has protesting her innocence and fighting extradition to the US. She is the daughter of Huawei's founder and CEO, 75-year-old Ren Zengfei.

Huawei CFO Meng Wanzhoua was arrested in December 2018 in Canada on charges in the initial Department of Justice indictment against the Chinese tech company. She is protesting her innocence and fighting extradition to the US. She is pictured wearing a court-ordered ankle monitor last month

The new indictment also includes 'new allegations about Huawei and its subsidiaries' involvement in business and technology projects in countries subject to sanctions, such as Iran and North Korea'.

The DoJ asserts that the Chinese company even tired to cover up the fact they were doing business with such countries, by using code names. 'A2' reportedly referred to Iran, and 'A9' is alleged to have referred to North Korea.

The new indictment is the latest effort in a global campaign by the United States against the company, which Washington has warned could spy on customers for Beijing. The United States also placed Huawei on a trade blacklist last year, citing national security concerns.

'The indictment paints a damning portrait of an illegitimate organization that lacks any regard for the law,' U.S. Senate Intelligence Committee chairman Richard Burr and vice chairman Mark Warner said in a joint statement.

The Republican and Democratic Senators called it 'an important step in combating Huawei's state-directed and criminal enterprise.'

In a statement on Tuesday, the DoJ alleges that Huawei's 'campaign' to steal trade secrets from US competitors formed part of their global growth strategy.

The DoJ statement alleges that Huawei even launched a policy 'instituting a bonus program to reward employees who misappropriated intellectual property from competitors.'

Prosecutors allege some Huawei employees entered into confidential agreements with the six US companies, before violating such agreements by then handing over the information to the Chinese tech giant.

Thus, the DoJ statements alleges that 'Huawei's efforts to steal trade secrets and other sophisticated US technology were successful.'

Trump administration officials, increasingly intent on preventing China from global technological domination, have urged allies not to use Huawei hardware

'As a consequence of its campaign to steal this technology and intellectual property, Huawei was able to drastically cut its research and development costs and associated delays, giving the company a significant and unfair competitive advantage,' the statement goes on to say.

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

Huawei, one of the largest tech firms and a major telecom equipment maker, has been blacklisted by Washington amid concerns of its ties to the Chinese government and intelligence services.

New charges have been filed in the US against Huawei (Dominic Lipinski/PA)

Earlier this week, White House national security adviser Robert O'Brien alleged that Huawei builds secret back doors into its hardware that allow it to covertly access mobile-phone networks around the world.

'We have evidence that Huawei has the capability secretly to access sensitive and personal information in systems it maintains and sells around the world,' O'Brien told the Wall Street Journal.

US officials say that Huawei's back door allows the company to access network data without the carrier's knowledge, potentially giving the Chinese government a potent spy tool.

Huawei denied the allegations, telling the Journal that it 'has never and will never do anything that would compromise or endanger the security of networks and data of its clients.'

The U.S. has long tried to convince its allies, such as the U.K. and Germany, to ban the use of Huawei telecom equipment in the building of 5G networks.

Germany's legislature is set to vote in the coming weeks on a bill that would allow Huawei full access to its 5G market if the company provides security guarantees.