China said Thursday that ``malicious slander'' is behind an order by the US 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 US 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 US allegations of espionage and intellectual property theft, calling them ``completely malicious slander.''

The US 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 US presidential election in November.

Wang did not comment on speculation about whether a US 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 US 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.