It supplied 80% of the rare earths imported by the United States from 2014 to 2017.
The evaluation feeds into a debate triggered by USA demands that companies in Europe and other allied nations shun Huawei as a 5G equipment supplier because of Washington's fears it could compromise intelligence services.
It is not unusual for China to summon representatives of foreign and domestic companies, sometimes in groups, to make its views heard.
Suspected to be a retaliative move to the US Commerce Department's "entity list" released last month - which included the banning of Chinese tech giant Huawei and numerous other companies for national security purposes - China's list will only target those that break the law.
One source with another United States technology company in China who was briefed by colleagues on the firm's meeting said that the tone was "much softer" than expected.
It is worth to mention that Huawei, is developing its own system which will reportedly be called "HongMeng" OS in China and "Ark" or "Oak" OS in other parts of the world.
The development comes after the USA government moved to curb Huawei Technologies Co.'s ability to sell equipment in the US and buy parts from suppliers there, potentially crippling one of China's most successful global companies.
The New York Times reported that other companies summoned for meetings last Tuesday and Wednesday included U.S. computer maker Dell Technologies, South Korea's Samsung Electronics and SK Hynix, and British chip designer ARM, which last month halted supplies to Huawei. Dell did not immediately respond on Sunday to an emailed request for comment and a spokesperson for ARM could not immediately be reached.
Mnuchin, as reported by Reuters, he went on to state that "If China wants to move forward with the deal, we're prepared to move forward on the terms we've done".
"Based on what I know, China is building a management mechanism to protect China's key technologies", Hu Xijin, the influential editor of the Chinese daily Global Times, said Saturday on Twitter.
China plans to create a new system to reduce threats to national security related to technology, according to the official Xinhua News Agency, as trade tensions between the world's two largest economies escalate. "This is a major step to improve its system, and also a move to counter the US crackdown".
"We expect export growth to remain positive in June, likely supported by continued front-loading of China's USA -bound exports, " said Lu Ting, chief China economist at Nomura Holdings Inc.in Hong Kong.
Hu did not cite any named sources in his tweet.