China has detained a top security official for passing sensitive information to the United States in the highest-level spy case involving the two countries since the 1980s, reports said.
Citing an unnamed "person with knowledge of the case," The New York Times said the official, who was arrested earlier this year, was believed to be an employee in the Ministry of State Security, China's main intelligence agency.
Hong Kong's New Way magazine said the detained official was a secretary to a vice minister at the ministry.
The vice minister, who was not named, has also been suspended from duty, the New Way report said.
"What is unbelievable is that the person involved in this spy case is a secretary to a vice minister who is handling China's top secrets, which means all the confidential documents sent to the vice minister pass through the secretary first," the magazine said.
"The incident has caused the concerns and worries of Chinese top leadership, and (President) Hu Jintao has ordered an investigation to get to the bottom of the matter," the magazine said, adding that Hu was "shocked and angry."
The magazine said the official was recruited by the CIA when he studied in the United States.
New Way described it as the highest-level spy case involving China and the United States since China's Yu Qiangsheng defected in 1985.
The United States and Chinese governments have not given any hint publicly of the discovery of the spying suspect. Secretary of State Hillary Clinton, visiting Oslo on Friday, declined to comment on the reports.
The unnamed official was detained around the time that the Communist Party was dealing with a fragile moment in relations with the United States, The Times noted.
In February, a former Chinese police chief drove to the US consulate in Chengdu to present evidence allegedly linking the wife of a top Communist Party leader, Bo Xilai, to the killing last year of a British businessman.
The police chief, Wang Lijun, was escorted to Beijing by officials from the Ministry of State Security after spending a night in the consulate.
It is unclear what kind of information the detained Chinese official is suspected of having given to the United States and whether that information had compromised any operations by the Chinese government, The Times said.
A senior US administration official, speaking on the condition of anonymity, said the detention came during the same period as a series of investigations begun after the revelations in the Bo affair, the report said.
The investigations, authorized by China's top leaders, have expanded beyond Bo to the Ministry of State Security and now include allegations of improper use of the security services by various Chinese officials and corruption, The Times noted.
It was not clear that the espionage case was related in any way to the other investigations, the report said.
"There is clearly some very intense stuff going on with the security ministry," the paper quoted the unnamed official as saying. "It's hard to tell exactly, but it's clearly maneuvering going on after Bo."
The reports came amid a growing strategic rivalry between the China and the United States, particularly in Asia.
US Defense Secretary Leon Panetta told a summit in Singapore earlier Saturday that the United States would shift the bulk of its naval fleet to the Pacific by 2020 as part of a new strategic focus on Asia.