Federal prosecutors on Thursday levied new charges against Huawei, accusing the world’s largest telecom equipment vendor of conspiring to steal trade secrets, ratcheting up pressure on the besieged Chinese company.

The allegations, which date back to 2000, include the theft of router source code, radio access network (RAN) technology, and acts of espionage.

Huawei is charged with conspiring to steal intellectual property from six U.S. companies, violating a racketeering law, and helping Iran track protesters with surveillance equipment during anti-government protests there in 2009.

Huawei denies any wrongdoing and described the latest charges as “political persecution” delivered by the Department of Justice. “These charges do not reveal anything new. They are based largely on resolved civil disputes from the last 20 years that have been previously settled, litigated, and in some cases, rejected by federal judges and juries,” the company wrote in a prepared statement.

The U.S. government and some of its allies have been waging a campaign against Huawei for many years, but those efforts reached a more prominent and forceful stature last year when it was banned from supplying 5G equipment to domestic operators and purchasing American-made products. Federal authorities, regulators, and many politicians view Huawei as a threat to America’s national security.

“The indictment paints a damning portrait of an illegitimate organization that lacks any regard for the law,” U.S. Sens. Richard Burr and Mark Warner said in a joint statement. “Intellectual property theft, corporate sabotage, and market manipulation are part of Huawei’s core ethos and reflected in every aspect of how it conducts business.”

Huawei previously filed a lawsuit against the U.S. government in March 2019, challenging an order that bans the government, its contractors, and suppliers from purchasing Huawei equipment or services. It described the latest charges as “selective, politically-motivated enforcement of the law, and contrary to common judicial conventions.” It added that “no company can become a global leader by stealing from others.”

The company maintains that none of its products or technologies were developed as a result of trade secrets theft.

The U.S. government has been attacking Huawei on multiple fronts outside of legal proceedings as well. A group of U.S. senators last month introduced a bill that would funnel more than $1 billion into 5G-related research and development in open RAN technologies that could elevate U.S. companies as an alternative to Huawei.

Earlier this month, White House economic advisor Larry Kudlow told The Wall Street Journal that the administration is working with large U.S. tech firms, including Dell Technologies, Microsoft, and AT&T, to create software for 5G networks in a bid to strengthen American leadership in 5G.

The flip side of this U.S. government-led effort, of course, is that the cellular RAN market is now tightly controlled by a small group of vendors, including Huawei, Ericsson, and Nokia, along with Samsung and ZTE to a lesser extent. Some large U.S. companies have tried and failed, and others like Cisco have repeatedly said it has no interest in building RAN equipment for 5G.

Last summer, Cisco CEO Chuck Robbins said it never even considered entering the RAN market and the U.S. government hadn’t asked the company to do so up to that point. During Cisco’s most recent earnings call, Robbins said the company has “spent a lot of time educating different folks in Washington about what technologies actually constitute an entire 5G network.”

Robbins said he is confident “the U.S. is in fine shape, both from a carrier deployment perspective … And I think we’re in a good position with the technology.” He also dismissed other ideas floating around about the U.S. government making investments in RAN or software vendors.