China has imposed sanctions on nine American defense firms, freezing their properties on the mainland as part of countermeasures against U.S. arms sales to Taiwan. The affected companies include Sierra Nevada Corporation, Stick Rudder Enterprises LLC, and Cubic Corporation, with all transactions involving these entities prohibited within China. This move follows the U.S. announcing plans to sell military equipment to Taiwan, which Beijing views as a violation of its sovereignty and the one-China principle. China's foreign ministry spokesperson urged the U.S. to cease its support for Taiwan's military, emphasizing that such actions threaten peace in the Taiwan Strait. Historically, the U.S. has been a key arms supplier to Taiwan, which maintains a de facto independent status despite China's claims. The sanctions reflect escalating tensions between the U.S. and China over Taiwan and broader geopolitical issues.