Huawei has confirmed it is suing the US government over a section of a defence bill passed into law last year that restricted its business in the United States.
Huawei said it had filed a complaint in a federal court in Texas challenging the constitutionality of Section 889 of the National Defense Authorization Act (NDAA), a section signed into law by the US president in August that banned federal agencies and their contractors from procuring its equipment and services.
"The US Congress has repeatedly failed to produce any evidence to support its restrictions on Huawei products. We are compelled to take this legal action as a proper and last resort," Huawei rotating chairman Guo Ping said in a statement.
"This ban not only is unlawful, but also restricts Huawei from engaging in fair competition, ultimately harming US consumers. We look forward to the court's verdict, and trust that it will benefit both Huawei and the American people."
While Huawei had very little market share in the US telecoms market before the bill, it viewed Section 889 as a stumbling block to addressing broader problems with Washington as its existence prevented any steps toward reconciliation.
"Lifting the NDAA ban will give the US Government the flexibility it needs to work with Huawei and solve real security issues," Mr Guo said.
The privately owned firm has embarked on a public relations and legal offensive over the past two months as Washington lobbies allies to abandon Huawei when building 5G mobile networks, centring on a 2017 Chinese law requiring companies cooperate with national intelligence work.
New Zealand has also moved to bar the firm from helping Spark build a 5G network after a Government Communications Security Bureau (GCSB) assessment last year.
Founder and chief executive Ren Zhengfei has said Huawei, the world's biggest telecoms gear maker, has never and will never share data with China's government.
The legal action and public relations outreach compare with a more restrained response in December emphasising "trust in justice" when its chief financial officer, Sabrina Meng Wanzhou, was arrested in Vancouver at US request.
The United States has accused Ms Meng - Mr Ren's daughter - of bank and wire fraud related to breaches of trade sanctions against Iran.
Huawei's legal action comes after Ms Meng appeared in court yesterday during which her lawyer expressed concerns that the allegations have a political character, raising US President Donald Trump's comments on the case.
Separately, Ms Meng, who is fighting extradition, is suing Canada's government for procedural wrongs in her arrest.
The case had strained relations with China, which this week accused two arrested Canadians of stealing state secrets in a move widely seen as retribution for Ms Meng's arrest.
While Ms Meng is under house arrest in Vancouver, it is unclear where the two Canadians are being detained in China.
Sources previously told Reuters that at least one of the Canadians did not have access to legal representation.
Change of tune
Mr Ren met international media for the first time in several years in mid-January, calling Mr Trump "great" and refraining from commenting directly on Ms Meng's case.
Shifting tone, Mr Ren in mid-February said Ms Meng's arrest was politically motivated and "not acceptable".
Long before Mr Trump initiated a trade war with China, Huawei's activities were under scrutiny by US authorities, according to interviews with 10 people familiar with the Huawei probes and documents related to the investigations seen by Reuters.