China has formally charged Hong Kong journalist Ching Cheong, 55, with spying for its rival Taiwan, the state news agency Xinhua has reported.
China accuses Ching Cheong of buying secret documents
Mr Ching, the chief China correspondent for Singapore's Straits Times, had been detained since late April.
China accuses him of buying information and passing it to Taiwan's intelligence services over a period of five years from 2000 to March 2005.
If Mr Ching is convicted, he could face the death penalty.
His wife, Mary Lau, has denied he did anything wrong, and was reported to be shocked by the charges.
The International Federation of Journalists in May expressed grave concern over Mr Ching's detention.
Christopher Warren, the head of the IFJ, accused China of a systematic crackdown on the media.
Chinese authorities quoted by Xinhua said Mr Ching had confessed during interrogation to spying.
Xinhua said he used a false name to buy "a great deal of information about China's political, economic and especially military affairs", using hundreds of thousands of dollars provided by Taiwan.
Mr Ching is accused of passing the information, which included classified documents, to Taiwan's intelligence services.
Beijing sees Taiwan as part of its territory and regularly threatens to invade if the island formally declares independence. The two sides are believed to operate extensive spying operations against each other.
Mr Ching, a Hong Kong citizen, was detained on 22 April in the southern Chinese city of Guangzhou.
China's foreign ministry said in May that he had admitted to spying.
But his wife, Mary Lau, said he had travelled to China to collect documents linked to the former Chinese leader, Zhao Ziyang.
Zhao, who died in January, was ousted for opposing the suppression of pro-democracy demonstrators in Tiananmen Square in 1989.
Mr Ching - who worked for the pro-Beijing Wen Wei Po newspaper until the Tiananmen crackdown - is the first Hong Kong journalist to be charged with spying since China resumed sovereignty over the territory in 1997.
Like many Hong Kong citizens, he also holds a British National (Overseas) passport.
But a spokeswoman for the British embassy in Beijing said China had not granted Britain consular access to speak with Mr Ching.
Mr Ching is the second employee of a foreign news organisation to be taken into custody by the Chinese government in a year.
New York Times researcher Zhao Yan was arrested by the Chinese authorities last October and charged with revealing state secrets. He is still awaiting trial.