Mubasher: Chinese smartphone maker Huawei sued the US government on Thursday, citing an “unconstitutional” law which limited its US operations.

Huawei lodged a complaint in US District Court in Texas, in challenge to Section 889 of the National Defense Authorization Act (NDAA), which was signed into law by President Donald Trump last August.

Huawei argued that the section could sharply hamper its ability to conduct business in the US despite no proof of wrongdoing.

“The US Congress has repeatedly failed to produce any evidence to support its restrictions on Huawei products,” Huawei’s Rotating Chairman Guo Ping said, adding that “we are compelled to take this legal action as a proper and last resort.”

The NDAA bans federal agencies and their contractors from procuring equipment and services from Huawei or its compatriot peer ZTE or doing business with any other companies using gear from the two firms as a “substantial or essential component” of their system.

“This ban not only is unlawful, but also restricts Huawei from engaging in fair competition, ultimately harming US consumers,” Guo added.

The lawsuit would ratchet up Huawei’s fight back against the White House which is bent on shutting the telecoms giant from global markets.

The move marks the latest confrontation between China and the US, in which both sides levied tariffs on billions of dollars in one another’s goods over the most of the past year.

Long before the beginning of the tariff salvo between the world’s two biggest economies, Huawei’s operations came under scrutiny by the US authorities, Thomson Reuters said, citing 10 sources familiar with the investigations and documents.

Although its share of the US market before implementing the bill was very little, the world’s largest telecoms gear manufacturer is pushing to have a major role in a global roll-out of fifth generation (5G) mobile networks and services.

Meanwhile, Washington lobbied its allies to exclude Huawei equipment when they set up 5G networks, centring on a Chinese law that requires firms cooperate with national intelligence work.