China's Ministry of Commerce (MOC) on Wednesday announced that four U.S. companies have been added to the unreliable entity list for selling arms to China's Taiwan region.

The decision was made by the unreliable entity list work mechanism in accordance with laws and regulations. The mechanism has also unveiled a series of restrictive measures targeting these companies, the MOC said in a statement.

The four companies in question are Pacific Rim Defense, AEVEX Aerospace, LKD Aerospace and Summit Technologies Inc.

They are prohibited from engaging in China-related import or export activities, and from making new investments within China, according to the MOC.

Senior executives of these companies are banned from entering China, and their existing work permits and residency qualifications in China will be nullified. No new permits or qualifications will be issued to these individuals, the MOC said.