Beijing expressed strong opposition on Thursday to Washington's second sale of arms this month to the Taiwan region, saying that what the United States has done to assist the Democratic Progressive Party authorities' attempt to seek "independence" through military buildup will only backfire.

The remark was made as the US State Department approved on Tuesday the sale to Taiwan of drones and missiles for an estimated $360 million. It was announced only two weeks after the US administration decided to sell $80 million worth of F-16 fighter jet spare and repair parts to the island.

Speaking at a regular news briefing, Foreign Ministry spokesman Lin Jian said the US' arms sales to the Taiwan region, regardless of China's opposition, seriously violate the one-China principle and the three China-US joint communiques, especially the Aug 17 Communique of 1982.

Such sales gravely undermine China's sovereignty and security interests, harm China-US relations and peace and stability across the Taiwan Strait, and send a gravely wrong message to "Taiwan independence" separatist forces, he said.

"China strongly condemns and firmly opposes the US' frequent arms sales to Taiwan, which embolden the DPP authorities as they stick to the 'Taiwan independence' position and make deliberate provocations on the one-China principle."

It shows once again that the biggest threat to cross-Strait peace and stability, and the biggest source of damage to the cross-Strait status quo, are the separatist moves for "Taiwan independence "and connivance and support for such moves from US-led external forces, Lin said.

Noting that the Taiwan question is at the core of China's core interests, and the first red line that cannot be crossed in China-US relations, Lin said no one should underestimate China's firm determination and strong ability to oppose "Taiwan independence "and safeguard its sovereignty and territorial integrity.

"China urges the US to ... stop the dangerous trend of arming Taiwan, stop its connivance and support for 'Taiwan independence' separatist forces, and stop endangering cross-Strait peace and stability."