Hackers broke into Fox's political Twitter account early Monday, posting updates saying President Barack Obama had been assassinated.
A series of six tweets coming from the FoxNewsPolitics account reported that Obama had been shot to death in Iowa and the shooter was unknown.
In a statement posted on its website later Monday morning, Fox News called the tweets "malicious" and "false." It said the hacking is being investigated.
Obama plans to spend the July Fourth holiday at a barbecue at the White House with military families and administration staffers.
Fox's political Twitter account has more than 34,000 followers.