China yesterday ordered the United States to close its consulate in the western city of Chengdu, ratcheting up a diplomatic conflict at a time when relations have sunk to their lowest level in decades.
The move was a response to the Trump administration's order for Beijing to close its consulate in Houston after Washington accused Chinese agents of trying to steal medical and other research.
The Chinese Foreign Ministry appealed to Washington to reverse its "wrong decision".
Chinese-US relations have soured amid a mounting array of conflicts over trade, the handling of the coronavirus pandemic, technology, spying accusations, Hong Kong and allegations of abuses against Chinese Muslims.
"The measure taken by China is a legitimate and necessary response to the unjustified act by the United States," said Foreign Ministry spokesman Wang Wenbin.
"The current situation in Chinese-US relations is not what China desires to see. The United States is responsible for all this.
"We once again urge the United States to immediately retract its wrong decision and create necessary conditions for bringing the bilateral relationship back on track."
Mr Wang claimed some consulate personnel "interfered in China's internal affairs and harmed China's security interests" but gave no details and insisted had Beijing complained "many times" to Washington about that.
Meanwhile, the US State Department sent out a notice warning Americans in China of a "heightened risk of arbitrary detention".
"US citizens may be subjected to prolonged interrogations and extended detention for reasons related to 'state security,'" the notice said.
Americans may be detained or deported for "sending private electronic messages critical" of the Chinese government, it warned.
The US consulate in Chengdu is responsible for monitoring Tibet and other areas in the southwest inhabited by non-ethnic Chinese minorities that are considered especially sensitive by Beijing.
Asian stock markets, already uneasy about the uncertain pace of recovery from the pandemic, fell yesterday on the news of the closure.
China's market benchmark, the Shanghai Composite Index, lost 3.9pc. Hong Kong's main index declined 2.2pc.
"Alongside the eviction of the Houston Chinese Consulate, the risk of the US-China conflict escalating into a 'cold war' is worrying," Hayaki Narita of Mizuho Bank said.