The United States is blacklisting four companies for assisting in the training and development of the Chinese military.

Two of the companies are located in China and two are located in the UK, according to a notice issued by the Commerce Department.

China’s Global Training Solutions and Smartech Future, as well as the UK’s Grace Air and Livingston Aerospace, will be added to the department’s trade restriction list due to their relationship with the Test Flying Academy of South Africa, which the posting says trained Chinese military forces using North Atlantic Treaty Organization (NATO) sources.

“This activity is contrary to the national security and foreign policy interests of the United States,” the statement reads.

The Commerce Department maintains that the actions are necessary to prevent American expertise and technology from being exploited by communist China, officially named the People’s Republic of China (PRC).

“Preventing American know-how from training PRC military pilots and U.S. technology from aiding Russia enhances U.S. national security,” said Assistant Secretary of Commerce Matthew Axelrod in a prepared statement on July 2.

The department also blacklisted two companies from the United Arab Emirates (UAE) for evading trade rules and delivering U.S. goods to Russia.

The Test Flying Academy of South Africa said that the Commerce Department had engaged in “unfair harassment” of the company for more than a decade due to the company’s refusal to divulge the personal information of those it did business with.

“TFASA has always obeyed the law in any and all jurisdictions in which it operates, and extensive consultations with legal advisers in those jurisdictions confirm that,” the company said in a statement.

“The imposition of the restrictions is an arbitrary determination and does not imply that any crime has been committed. As such TFASA does not employ any U.S. nationals, and none of its activities involve any American nationals, businesses, goods, transhipments, or services whatsoever.”

Companies wishing to ship U.S. goods and technology to those on the Entity List are required to obtain licenses to do so. U.S. exporters are also required to conduct additional due diligence before sending items to companies on the related Unverified List and may have to apply for more licenses.

The Commerce Department also added 13 companies to its Unverified List, including eight from China, because U.S. export control officers could not complete on-site visits to determine whether they could be trusted to receive U.S.-origin technology and other goods.

At the same time, the department removed eight companies from the Unverified List, including six from China, one from the UAE, and one from Russia.

Reuters contributed to this report.