The US has ordered China to close its consulate in Houston, Texas, by Friday - a move described as "political provocation" by Beijing.
The US State Department said the decision was taken "in order to protect American intellectual property".
But China's foreign ministry spokesman Wang Wenbin said it was "outrageous and unjustified".
The statements came after unidentified individuals were filmed burning paper in bins in the building's courtyard.
Tensions have been rising between the US and China for some time. President Donald Trump's administration has clashed repeatedly with Beijing over trade and the coronavirus pandemic, as well as China's imposition of a controversial new security law on Hong Kong.
Then on Tuesday, the US Department of Justice accused China of sponsoring hackers who had been targeting labs developing Covid-19 vaccines. Two Chinese nationals, who allegedly spied on US research companies and got help from state agents for other thefts, have been charged.
Why did the US say it was closing the consulate?
The US State Department released a statement shortly after Wang spoke on Wednesday.
"We have directed the closure of PRC [People's Republic of China] Consulate General Houston, in order to protect American intellectual property and American's private information," State Department spokeswoman Morgan Ortagus said.
She added the US "will not tolerate the PRC's violations of our sovereignty and intimidation of our people, just as we have not tolerated the PRC's unfair trade practices, theft of American jobs, and other egregious behaviour".
Ortagus also pointed to the Vienna Convention on diplomatic relations, under which states "have a duty not to interfere in the internal affairs" of a host country.
The consulate is one of five in US, not counting the embassy in Washington DC. It is unclear why this one was singled out.
How did China react to the order?
China called the decision "an unprecedented escalation", saying it violated international law. Wang went on to say Washington had been "shifting the blame to China with stigmatisation and unwarranted attacks".
He urged the US to reconsider, saying if it insists "on going down this wrong path, China will react with firm countermeasures".
"In reality, in terms of the number of Chinese and American embassies and consulates in each other's countries and the number of diplomatic and consular staff, the US has far more people working in China," Wang said.
Chinese state media the Global Times began running a poll on which US consulate to close in response.
Source: BBC
BDST: 1740 HRS, JULY 22, 2020
AP
