BEIJING, Aug. 21 (Xinhua) -- China on Wednesday urged the United States to immediately cancel the planned arms sales to Taiwan, saying China will take all necessary measures to defend its own interests including imposing sanctions on U.S. companies involved in the planned sales.

The U.S. Defense Department on Wednesday officially notified the U.S. Congress of the plan to sell 66 F-16 fighters and relevant equipment worth around 8 billion U.S. dollars to Taiwan and to provide support.

"China firmly opposes the plan and has lodged solemn representations and protests to the U.S. side," Foreign Ministry spokesman Geng Shuang told a press briefing.

The U.S. arms sales plan seriously violated international laws and basic norms governing international relations, as well as the one-China principle and the three China-U.S. joint communiques, especially the August 17 Communique, Geng said.

"[Such a move] constitutes severe interference in China's internal affairs, and undermines China's sovereignty and security interests."

The spokesman said the Taiwan question concerns China's sovereignty and territorial integrity, which is associated with China's core interests. "China has firm determination to safeguard its own national sovereignty, unity and security."

Geng urged the U.S. side to abide by the one-China principle and relevant provisions laid out in the three China-U.S. joint communiques, "immediately cancel the aforementioned arms sales plan, cease arms sales to Taiwan and sever military ties with the island."

"Otherwise, all the ensuing consequences will be born by the U.S. side," Geng added.