China's CCTV News has deleted an "incorrect" tweet on its account that said a former security chief is being investigated for corruption.
CCTV claimed its Twitter account had been hacked after the post reported that President Xi Jinping had set up a unit to investigate Zhou Yongkang.
The episode will embarrass the state broadcaster and fuels rumours that have swirled for months about Mr Zhou.
China blocks Twitter - some state media use it to reach foreign audiences.
"President Xi Jinping has set up a special unit to investigate corruption allegations against the retired leader Zhou Yongkang," read the swiftly deleted tweet, according to a screen grab on freeweibo.com, which is run by an anti-censorship site, greatfire.org.
The tweet, which appeared on Monday evening, seemed to refer to an article in Hong Kong's South China Morning Post newspaper.
Within a couple of hours the tweet had been removed.
"The CCTV News Twitter account was targeted on 21 October and used illegally to post incorrect information copied from other sources," CCTV said through its English-language Twitter account.
"The unauthorised information was deleted."
Reuters news agency quoted CCTV spokeswoman Zhang Xiaojian as confirming that one of the broadcaster's Twitter accounts had been hacked, but did not elaborate.
The CCTV Twitter account has more than 2,500 followers.
In contrast, it has 9.9 million followers on its main account on Sina Weibo, China's version of Twitter.
Mr Zhou retired from the Communist Party's Politburo Standing Committee during a sweeping leadership reshuffle last November.
The reports that he is under investigation for alleged corruption have not been officially confirmed.
President Xi has identified corruption as a threat to the survival of the ruling Communist Party, and has promised to crack down on both high-flying "tigers" and lowly "flies".