Shanghai's Youth Daily quoted tournament official Yang Yibin, saying that the online threat made against the Swiss world number one is being taken seriously by the police.
An internet user under the pseudonym of 'Blue Cat Polytheism Founder 07' vowed to assassinate Federer 'for the purpose of tennis extermination', submitting his message with a gruesome image of the 31-year-old being decapitated.
"We hope that it was an oral threat only, and the fan won't take substantive action. However, we have to take it seriously," Yang Yibin was quoted as saying.
The tournament begins this weekend, with the world's leading players including Federer, Novak Djokovic and Andy Murray all expected to play.
In a statement from the Shanghai Masters organisers, the tournament stressed that proper measures were in place.
''We are fully aware of the comments that have been made and we take all such issues seriously,'' the statement said. ''The Shanghai Rolex Masters has security in place for our players and every precaution is taken to make sure players are kept safe and comfortable and allowed to do the job they are here for; to play tennis and provide their fans with the thrill of watching them in action.''