BEIJING >> China said today that “malicious slander” is behind an order by the U.S. government to close its consulate in Houston, Texas, maintaining that its officials never operated outside ordinary diplomatic rules.

Foreign ministry spokesperson Wang Wenbin said the move against the consulate, the first one China opened in the U.S. after the establishment of diplomatic ties in 1979, goes against the basic norms of international relations.

“This is breaking down the bridge of friendship between the Chinese and American people,” Wang told reporters at a daily briefing.

He dismissed U.S. allegations of espionage and intellectual property theft, calling them “completely malicious slander.”

The U.S. on Tuesday ordered the consulate closed within 72 hours, alleging that Chinese agents had tried to steal data from facilities in Texas, including the Texas A&M medical system and The University of Texas MD Anderson Cancer Center in Houston.

The move was a dramatic escalation of the growing tensions between the world’s two largest economies as President Donald Trump directs blame and punitive measures at China ahead of the U.S. presidential election in November.

Wang did not comment on speculation about whether a U.S. consulate in China would be ordered closed in response, and which one might be targeted.

“China will surely take necessary measures to safeguard its legitimate rights and interests,” he said, without elaborating.

The U.S. has an embassy in Beijing and consulates in five other mainland cities: Shanghai, Guangzhou, Chengdu, Shenyang and Wuhan. It also has a consulate in Hong Kong, a Chinese territory.

Relations between the U.S. and China have nose-dived in recent months over the coronavirus pandemic and disputes over trade, human rights, Hong Kong and Chinese assertiveness in the South China Sea.

China’s relations with Britain have also become increasingly strained, in part over Hong Kong, a former British colony returned to China in 1997.

Wang criticized the U.K. for opening a pathway to citizenship for up to 3 million residents of the city of 7.5 million people. He said China might stop recognizing the British National Overseas passport that those 3 million hold or are eligible to get.

Britain on Wednesday announced a January start date for new rules that will allow holders of the passport to live and work in the U.K. and eventually obtain citizenship.

China says Britain pledged in an agreement between the two that it would not grant residency to holders of the passport.

“Since the British side violated its commitment first, China will consider stopping recognition of the British National Overseas passport as a valid travel document,” Wang said.

Britain adopted the new immigration rules after China imposed a new national security law on Hong Kong at the end of June. U.K. officials said the country would not abandon its responsibilities to the people of its former colony.