BEIJING, Aug. 5 (Xinhua) -- China on Thursday expressed firm opposition to the U.S. State Department's approval of an arms sale to Taiwan, and has lodged solemn representations with the U.S. side, according to a Foreign Ministry spokesperson.

China will take legitimate and necessary counter-measures in light of the development of the situation, said the spokesperson.

That came after the Pentagon's Defense Security Cooperation Agency announced on August 4 that the U.S. State Department had approved the sale of 40 Medium Self-Propelled Howitzer artillery systems to Taiwan in a deal valued at $750 million.

Noting that Taiwan is an inalienable part of China's territory, the spokesperson said that the United States is interfering in China's internal affairs and undermining China's sovereignty and security interests by selling arms to the Taiwan region.

The move runs counter to international law and the basic principles of international relations, and violates the one-China principle and the provisions of the three China-U.S. joint communiques, particularly the August 17 Communique, the spokesperson said.

The spokesperson said the move sends erroneous signals to "Taiwan independence" separatist forces, and severely jeopardizes China-U.S. relations and peace and stability across the Taiwan Strait. "China is firmly opposed to this and has lodged solemn representations with the U.S. side."

The spokesperson said that China urges the U.S. side to honor its commitments, earnestly abide by the one-China principle and the three China-U.S. joint communiques, cease arms sales to and military interactions with Taiwan, and immediately revoke relevant arms sales to Taiwan, lest more damage be dealt to China-U.S. relations and peace and stability across the Taiwan Strait.