China urged the United States on Wednesday to immediately revoke the sale of four armed MQ-9 Reaper drones to Taiwan, vowing to take legitimate and necessary response in light of the development of the situation.

The weapons transfer is the first such sale since the Trump administration eased the US policy to restrict the export of sophisticated and closely guarded drone technology.

US arms sales to Taiwan violated the one-China principle and the three China-US joint communiques, especially the Aug 17 Communique, and undermined China's sovereignty and security interests, Foreign Ministry spokesman Wang Wenbin told a daily news conference.

China firmly opposes the sales, which sent out the wrong signals to "Taiwan independence" separatist forces, and damaged China-US relations as well as peace and stability across the Straits, Wang said.

China urges the US to stop arms sales to and military ties with Taiwan, and cancel the relevant arms sale plan to avoid further harming bilateral ties and cross-Straits peace and stability, he said.