The U.S. Department of Justice is investigating if Chinese technology company Huawei has violated U.S. sanctions in relation to Iran, the Wall Street Journal reported.

Information is not available as to how far the department’s criminal probe had advanced and what allegations the federal agents were exploring. ZTE, the rival of Huawei, is already facing the music due to its earlier supply to Iran.

Huawei, the largest telecom equipment maker and third largest smartphone maker, was not immediately available for comment. Huawei is already under pressure from telecom operators such as AT&T which decided against sourcing smartphones from the China based telecom equipment company.

U.S. authorities last week banned American companies from selling components to Chinese smartphone maker ZTE for seven years, saying the Chinese company had broken a settlement agreement related to Iran sanctions with repeated false statements – a move that threatens to cut off ZTE’s supply chain.

ZTE, a competitor of Huawei, has faced the ban due to ZTE’s failure to comply with an agreement with the U.S. Commerce Department reached last year after it pleaded guilty in federal court to conspiring to violate U.S. sanctions by illegally shipping U.S. goods and technology to Iran.

In 2016, the Commerce Department made documents public that showed ZTE’s misconduct and also revealed how a second company, identified only as F7, had successfully evaded U.S. export controls.

Ten lawmakers in a 2016 letter to the Commerce Department said they believed F7 to be Huawei.

In April 2017, lawmakers sent another letter to Commerce Secretary Wilbur Ross asking for F7 to be publicly identified and fully investigated.

ZTE said on Wednesday it planned to take “certain actions” under U.S. laws following a ban by the U.S. government on American firms doing business with the company. It is believed that the ZTE ban will impact chipset company Qualcomm and OS company Google other component suppliers to ZTE.

The US president Donald Trump blocked Broadcom from acquiring Qualcomm due to the government strategy to protect the interest of American corporates. The US administration never wanted China to rule the wireless space and pose threats to Americans. It did not talk about the dominance of Huawei in the global wireless space.

Recently, FCC said it would like to block some telecom equipment companies from selling equipments to government projects. FCC did not mention about Huawei or ZTE during the proposal.

Baburajan K