China said on July 27 that it was unaware of the case of Singaporean Dickson Yeo Jun Wei who has been charged in the United States for being an illegal agent of China.
China also urged the United States to stop its "smear" campaign.
Chinese foreign ministry spokesperson Wang Wenbin made these remarks at a regular press briefing in response to press queries about the case.
Wang said it was "open knowledge" that the U.S. conducts espionage activities.
"It is open knowledge that the US runs an aggressive espionage and theft programme all across the globe, sparing not even its allies. There's solid evidence for this," Wang said.
"The world has seen the act of the real thief crying 'stop the thief' too many times."
"We urge the U.S. to stop using the so-called espionage issue to smear China."
Wang added that the U.S. has been "hyping up" such issues.
"I'm not aware of what you just mentioned," he said, when asked about Yeo's case.
"But I would like to point out that lately, U.S. law enforcement has been busy hyping up the so-called China infiltration and espionage issues to the point of paranoia."
Yeo pleaded guilty on July 24 in the U.S. to working for Chinese intelligence.
The former National University of Singapore (NUS) Lee Kuan Yew School of Public Policy PhD student said he was recruited by Chinese intelligence operatives in Beijing.
From about 2015, he helped to collect non-public sensitive information about the U.S. military and government via a fake consultancy company he set up with Chinese assistance.
Wang's remarks came on the same day that Beijing announced the U.S. consulate in Chengdu was closed.
China ordered the facility to shut.
This tit-for-tat action came after the Chinese consulate in Houston, Texas was forced to be emptied out.
The closure of the Chengdu consulate is China's "legitimate and necessary response" to the "unjustified U.S. act" of closing China's consulate in Houston, Wang told reporters.
Wang said some U.S. staff members at the Chengdu consulate "were engaged in activities outside of their capacity, interfered in China's internal affairs, and endangered China's security and interests".
Washington officials also said the same thing: There had been unacceptable efforts by the Chinese consulate in Houston to steal U.S. corporate secrets and proprietary medical and scientific research.