Tan voiced strong opposition to the US sale of weapons to Taiwan and said the US action has gravely violated the one-China principle and the three China-US joint communiqués, severely jeopardized China's sovereignty and security interests, and seriously undermined the relations between the two countries and two militaries as well as peace and stability in the Taiwan Straits.
On December 6, the US government approved two arms sales worth 430 million USD to Taiwan.