The Chinese mainland condemned on Monday a recent visit by a senior official of the Taiwan region to the United States, warning that any attempt to engage in "Taiwan independence" separatist activities are doomed to fail and urging Washington to stop sending wrong signals to separatist forces.

Foreign Ministry spokesman Lin Jian made the remarks on Monday at a daily news briefing after Chiu Chui-cheng, an official from the Taiwan region, met with members of Congress of both parties during a recent visit to the United States and described Chinese mainland as the biggest threat to peace and stability across the Taiwan Strait during a speech at a US think tank.

"There is only one China in the world, and Taiwan is an inalienable part of China's territory — this is the real status quo across the Taiwan Strait," Lin said.

"Taiwan independence" separatist forces and their connivance and support by external forces pose the greatest threat to peace and stability across the Taiwan Strait, he added.

The spokesman voiced firm opposition to any form of official exchanges and military collusion between the US and Taiwan region, vowing that China will firmly defend its national sovereignty and territorial integrity.

He urged Washington to strictly abide by the one-China principle and the three China-US joint communiques, and to stop sending any wrong signals to the "Taiwan independence" separatist forces.

No matter how the Democratic Progressive Party authorities hype up the so-called threat from the Chinese mainland, they cannot change the fact that both sides of the Strait belong to one China, Lin added.