Earlier this month, the Commerce Department banned ZTE, China's second-biggest network equipment maker, from buying US -made components as punishment for violating a sanctions settlement over transactions with Iran and North Korea.
The Journal report gave no details about the investigation.
Major US telecoms companies have already steered clear of the two Chinese firms, sometimes on the strong suggestions of US officials. The New York Times has reported that the company has been subpoenaed by the Commerce and Treasury Departments over alleged violations of Iran and North Korea sanctions.
The U.S. government's investigation into sanctions violations by ZTE following reports by in 2012 that the company had signed contracts to ship millions of dollars' worth of hardware and software from some of the best-known U.S. technology companies to Iran's largest telecoms carrier.
Last year, the White House blocked two proposed mergers between US companies and Chinese companies. A Huawei spokesman declined to comment.More news: Philadelphia 76ers: 3 takeaways from Game 3 vs. Heat
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China's ZTE is seeking a resolution to a U.S. ban on selling it parts and software that it has said threatens its survival. Ciena and Infinera, of course, compete with both Huawei and ZTE in worldwide markets (except China). "In 30 years, not a single operator has experienced a security issue with our equipment".
In a 2016 letter to the Commerce Department, 10 US lawmakers said F7 was believed to be Huawei, citing media reports.
Issues and warnings against Huawei have come from presumptions that the company has ties to the Chinese government.
The sales ban also could disrupt a multibillion-dollar revenue flow to USA companies such as Qualcomm Inc. that supply chips, software and other technology. Both Huawei, which is the third largest smartphone manufacturer in the world, and ZTE, deny that they are a national security threat to the U.S.
Despite the setbacks, Huawei said last month that 2017 net income rose 28 percent and that growth in markets from the Middle East to Africa have it targeting record sales of $102.2 billion this year.