WASHINGTON, June 12 (Reuters) - The Biden administration on Monday added 43 entities to an export control list, including Frontier Services Group Ltd, a security and aviation company previously run by Erik Prince, for training Chinese military pilots and other activities that threaten U.S. national security.

The Test Flying Academy of South Africa, a flight school under scrutiny by authorities in Britain for recruiting British ex-military pilots to train Chinese military fliers, was also added to the U.S. Commerce Department's Entity List.

Companies on the list are restricted from receiving U.S. exports for activities deemed contrary to U.S. interests.

The new listings include Frontier Services Group sites in China, Kenya, Laos and the United Arab Emirates; TFASA units in South Africa, China, the United Arab Emirates and the United Kingdom; and aerospace and defense conglomerate Aviation Industry Corporation of China (AVIC) entities in China and South Africa.

The companies could not immediately be reached for comment.

In addition to recruiting Western pilots to train People's Liberation Army pilots on Western aircraft maneuvers, companies were added to the list for acquiring U.S.-origin items in support of China's military modernization, including hypersonic weapons development and hypersonic flight modeling, the Commerce Department said in a release.

"It is imperative that we prevent China from acquiring U.S. technologies and know-how to enable their military modernization programs," Matthew Axelrod, a Commerce official, said in a statement.

Thirty-one Chinese entities in total were added to the list.

Shanghai Supercomputing Technology Co Ltd was added for offering cloud-based supercomputing capabilities to support hypersonics research.

Nine Chinese and Pakistani companies were added for contributing to Pakistan’s ballistic missile program and other weapons contributions.

And two companies were added for enabling China to carry out human rights abuses, including as part of its repression of the Ugyhur Muslims and members of other minority groups in Xinjiang, western China.

Ryan Wende Science and Technology Co in Beijing procures and distributes mobile phone inspection software, fingerprint analysis technology, biostatistics software and DNA testing items to Public Security Bureaus throughout China, the Commerce Department said.

Xinjiang Kehua Hechang Biological Science and Technology Co Ltd acquires and distributes biotech items to the Xingjiang Production and Construction Corps, which is on the entity list, and Public Service Bureaus in Xinjiang.

U.N. experts and rights groups estimate that over a million people, mainly Uyghurs and Muslim minorities, have been detained in camps in China's western region of Xinjiang in recent years, with many saying they were subject to ideological training and abuse.

China has denied all accusations of abuse.

The U.S. also removed Fiber Optic Solutions in Latvia from the Entity List on Monday. Fiber Optic Solutions, which produces fiber optic gyroscopes and other equipment, was added in December for its contributions to the Russian military and/or defense industrial base.

Erik Prince, a private security executive, was the founder of the security firm Blackwater. According to his LinkedIn profile, Prince was vice chair of Frontier Services Group from 2014 to 2021.