BEIJING - A journalist with China's official Xinhua news agency on Wednesday accused the head of a key state-owned firm of "corruption involving a huge amount".
The allegations - in the form of an open letter to the ruling Communist Party's disciplinary department - come as China's new leaders repeatedly pledge to stamp down on graft.
But within hours of Wang Wenzhi detailing his allegations on China's Twitter-like Sina Weibo, his account was blocked and could no longer be accessed.
Xinhua's own website itself carried a report on his posting, but then took it down.
Chinese authorities have in some cases encouraged whistle-blowers to reveal alleged corruption, but have also sometimes cracked down on them.
Wang accused Song Lin, chairman of China Resources (Holdings) Co, of losing the firm billions of yuan (hundreds of millions of dollars) in a deal to buy assets from another company.
"Song Lin and other senior managers who participated in the acquisition neglected their duty and are suspected of graft involving a huge amount," Wang wrote.
Wang said he was compelled by his "sense of responsibility and conscience as a Chinese citizen and journalist" to report the scandal, adding he would publish more evidence later.
"I am very well aware of the huge risks this reporting under my real name could bring to my family and myself in current China," he wrote in the posting.
"But I firmly believe that there is justice in China under the leadership of the party."